I just bought an amp clamp meter, and it states the error is "+/- 1.9% + 3 digits". What does the "3 digits" part mean?
I just bought an amp clamp meter, and it states the error is "+/- 1.9% + 3 digits". What does the "3 digits" part mean?
On 6/18/2020 6:33 PM, Commander Kinsey wrote:
I just bought an amp clamp meter, and it states the error is "+/- 1.9% + 3 digits". What does the "3 digits" part mean?
If your meter should read, say 1.875 A, the correct reading could
be anywhere from 1.872 to 1.878. This is a possible error in the
display presented to you in the analog-digital display conversion
process. The +/-1.9% possible error is about the measurement
taken including - but not only - any error made by the sensor.
To put it another way: If the actual current is 1.875 A,
inaccuracies in the sensor and associated circuits may process it
as somewhere between 1.875 A +/-1.9%. The analog-digital process
may introduce a further error of +/- 3 counts in the least
significant display digit. Therefore a current of 1.875 A may be
displayed as anywhere from 1.836 to 1.913 A.
If your meter should read, say 1.875 A, the correct reading could
be anywhere from 1.872 to 1.878. This is a possible error in the
display presented to you in the analog-digital display conversion
process. The +/-1.9% possible error is about the measurement
taken including - but not only - any error made by the sensor.
To put it another way: If the actual current is 1.875 A,
inaccuracies in the sensor and associated circuits may process it
as somewhere between 1.875 A +/-1.9%. The analog-digital process
may introduce a further error of +/- 3 counts in the least
significant display digit. Therefore a current of 1.875 A may be
displayed as anywhere from 1.836 to 1.913 A.
Thanks, I wonder why all my other meters only list a % error. Is it included within it somehow, or are they just lying, or do some meters not have this error?
In article <op.0meweog5wdg98l@glass>, CFKinsey@military.org.jp says...
If your meter should read, say 1.875 A, the correct reading could
be anywhere from 1.872 to 1.878. This is a possible error in the
display presented to you in the analog-digital display conversion
process. The +/-1.9% possible error is about the measurement
taken including - but not only - any error made by the sensor.
To put it another way: If the actual current is 1.875 A,
inaccuracies in the sensor and associated circuits may process it
as somewhere between 1.875 A +/-1.9%. The analog-digital process
may introduce a further error of +/- 3 counts in the least
significant display digit. Therefore a current of 1.875 A may be
displayed as anywhere from 1.836 to 1.913 A.
Thanks, I wonder why all my other meters only list a % error. Is it included within it somehow, or are they just lying, or do some meters not have this error?
Most that use a digital meter should know the last digit is not accurate because of a rounding error. Say it shows 1.5 volts. It could be 1.45
to 1.55 or so and still show 1.5. Some meters such as the one under discussion is less accurate and can be 3 numbers high or low on the last digit. That is why on digital meters you should try to use a range that shows as many digits as you can.
-My several hundred dollar Fluke meter shows DC volts to be .05 % +- 1
digit.
-My several hundred dollar Fluke meter shows DC volts to be .05 % +- 1 digit.
The meters I have are not several hundred dollars, so are you saying they're only +/- 1 digit? Is the error much higher on the one under discussion because it's a clamp meter?
In article <op.0mfizcwhwdg98l@glass>, CFKinsey@military.org.jp says...>> > -My several hundred dollar Fluke meter shows DC volts to be .05 % +- 1But what I'm surprised at is a u5 multimeter (not clamp) not giving a digits error. Maybe precision on a simple voltmeter is cheap as chips nowadays?
digit.
The meters I have are not several hundred dollars, so are you saying they're only +/- 1 digit? Is the error much higher on the one under discussion because it's a clamp meter?
The larger error is because of the price difference. It costs more to> make a part that is .01 % than it does to make one that is 2 %. The
.01% parts may just be the 2 % ones that are hand sorted to .01%.
I am sure that the clamp part does play some part in how accurate the
meter is.
But what I'm surprised at is a u5 multimeter (not clamp) not giving a digits error. Maybe precision on a simple voltmeter is cheap as chips nowadays?
In article <op.0mg7zmz6wdg98l@glass>, CFKinsey@military.org.jp says...>>That didn't help. I interchange the two. I just want to know how close to the correct reading the readout is. Adding another digit doesn't improve anything if it's incorrect. And shooting all the bullets in one place doesn't help if they all miss.
But what I'm surprised at is a u5 multimeter (not clamp) not giving a digits error. Maybe precision on a simple voltmeter is cheap as chips nowadays?
You have to be careful how you throw precision and accurecy around.
A meter that shows 4 digits is more precice than one that shows only 3> digits, however the 4 digit one may only be 1% accurate and the 3 digit
one may be .5% accurate.
It is easy to get precision, but difficule to be accurate. Think of it
as shooting a gun. Precision may be how close the bullets land to each
other where ever they land on the target, but to be accurate the bullets
have to land on the center of the target. Such as all the bullets could
land very close to each other, but not even hit the target.
As I mentioned, a good meter will not have a digits error outside the +-
one digit due to rounding.
On Fri, 19 Jun 2020 23:55:42 +0100, Ralph Mowery <rmowery28146@earthlink.net> wrote:
In article <op.0mg7zmz6wdg98l@glass>, CFKinsey@military.org.jp says...
But what I'm surprised at is a u5 multimeter (not clamp) not giving a digits error. Maybe precision on a simple voltmeter is cheap as chips nowadays?
You have to be careful how you throw precision and accurecy around.
A meter that shows 4 digits is more precice than one that shows only 3
digits, however the 4 digit one may only be 1% accurate and the 3 digit
one may be .5% accurate.
It is easy to get precision, but difficule to be accurate. Think of it
as shooting a gun. Precision may be how close the bullets land to each
other where ever they land on the target, but to be accurate the bullets
have to land on the center of the target. Such as all the bullets could
land very close to each other, but not even hit the target.
As I mentioned, a good meter will not have a digits error outside the +-
one digit due to rounding.
That didn't help. I interchange the two. I just want to know how close to the correct reading the readout is. Adding another digit doesn't improve anything if it's incorrect. And shooting all the bullets in one place doesn't help if they all miss.
On 6/20/2020 4:29 AM, Commander Kinsey wrote:I'd need to contract OCD to understand that. There's only one thing in question here, how close is the reading to the correct value. You can't split that into two. 3.1416 is better than 3.14, and that's it. All you can state with a reading is it's correct to within a certain percentage.
On Fri, 19 Jun 2020 23:55:42 +0100, Ralph Mowery <rmowery28146@earthlink.net> wrote:
In article <op.0mg7zmz6wdg98l@glass>, CFKinsey@military.org.jp says...
But what I'm surprised at is a u5 multimeter (not clamp) not giving a digits error. Maybe precision on a simple voltmeter is cheap as chips nowadays?
You have to be careful how you throw precision and accurecy around.
A meter that shows 4 digits is more precice than one that shows only 3
digits, however the 4 digit one may only be 1% accurate and the 3 digit
one may be .5% accurate.
It is easy to get precision, but difficule to be accurate. Think of it
as shooting a gun. Precision may be how close the bullets land to each
other where ever they land on the target, but to be accurate the bullets >>> have to land on the center of the target. Such as all the bullets could >>> land very close to each other, but not even hit the target.
As I mentioned, a good meter will not have a digits error outside the +- >>> one digit due to rounding.
That didn't help. I interchange the two. I just want to know how close to the correct reading the readout is. Adding another digit doesn't improve anything if it's incorrect. And shooting all the bullets in one place doesn't help if they all miss.
Take pi as an example. It can be said that 3.14 is accurate as a
three-digit value, but 3.1416 is more precise because it has a
higher resolution.
OTOH, deriving it from 22/7 or 3.1429 has the same 5-digit
resolution and is just as precise as far as the number it
represents is concerned but is less accurate.
In this particular case, 3.1416 is both more precise and more
accurate than 3.14 but that's not always the case with measurements.
My mechanical slide caliper has a resolution of 0.001 inch. This
means that it can display measurements with a precision of 1 mil,
but that doesn't guarantee that a measurement taken with it will
be accurate to 1 mil. I may not always press the jaws snugly
enough and the scale may not be perfectly accurate.
I'd need to contract OCD to understand that. There's only one thing in question here, how close is the reading to the correct value. You can't split that into two. 3.1416 is better than 3.14, and that's it. All you can state with a reading is it's correct to within a certain percentage.
In article <op.0miefkhkwdg98l@glass>, CFKinsey@military.org.jp says...
I'd need to contract OCD to understand that. There's only one thing in question here, how close is the reading to the correct value. You can't split that into two. 3.1416 is better than 3.14, and that's it. All you can state with a reading is it's correct to within a certain percentage.
Try this.
A doctor does a very complicated operation on your left arm like a joint replacement. It all goes very well. Very precise.
However he should have done the operation on the right arm that was
causing trouble. Not accurate.
That is why a voltmeter can show 3 digits and be accurate to only the
last digit being in question by one number either way, but a 5 digit
volt meter can show many numbers, but if it is not calibrated corrctly
the 2nd digit to the 5 th digit could be way off and the meter not
accurate at all.
On Sat, 20 Jun 2020 16:24:41 +0100, Ralph Mowery <rmowery28146@earthlink.net> wrote:
In article <op.0miefkhkwdg98l@glass>, CFKinsey@military.org.jp says...
I'd need to contract OCD to understand that. There's only one thing in question here, how close is the reading to the correct value. You can't split that into two. 3.1416 is better than 3.14, and that's it. All you can state with a reading is it's correct to within a certain percentage.
Try this.
A doctor does a very complicated operation on your left arm like a joint
replacement. It all goes very well. Very precise.
However he should have done the operation on the right arm that was
causing trouble. Not accurate.
Nope, because the first one is 100% useless. I wouldn't call that precise at all, as he was out by half a metre.
That is why a voltmeter can show 3 digits and be accurate to only the
last digit being in question by one number either way, but a 5 digit
volt meter can show many numbers, but if it is not calibrated corrctly
the 2nd digit to the 5 th digit could be way off and the meter not
accurate at all.
Showing those extra two numbers is pointless if they're wrong. All that matters is how many volts difference between the actual voltage and what is shown.
You keep saying that it's only the accuracy that matters. That's
true to some - and only some - extent.
Showing those extra two numbers is pointless if they're wrong. All
that matters is how many volts difference between the actual voltage
and what is shown.
In article <U6sHG.61028$Nj4.43851@fx24.ams1>, nobody@nowhere.com says...
You keep saying that it's only the accuracy that matters. That's
true to some - and only some - extent.
Sometimes it is precision.
I worked at a company making polyester from raw materials. In a room
was a panel with about 10 temperature gauges. At a certain time all
gauges were marked and a sample of the material was sent to the lab. If
it came back good, then the object was to keep all the gauges on the
mark. It did not matter how far off the gauges were from the actual temperature. No mater how well we calibrated the guages there were
several other factors that we had no control over. Such as the
thermocouples they were connected to. The specifications were +- 3 deg
C. on the thermocouples from the factory. If the temperature varied
more than 1 deg C at 300 deg C it could mess up the material.
So the object was precision and not accuracy.
I just bought an amp clamp meter, and it states the error is "+/- 1.9% +
3 digits".a What does the "3 digits" part mean?
On 2020-06-20 17:58, Commander Kinsey wrote:
[...]
Showing those extra two numbers is pointless if they're wrong. All
that matters is how many volts difference between the actual voltage
and what is shown.
Engineers distinguish between accuracy, a measure of how close
a observed value is to the true value, and resolution, which
is a measure of the device's ability to resolve small changes.
Either specification is useful in its own right, and professional instrumentation will always have both specs. So even if the
last digit or two of a measuring device are not accurate, they
may still be useful.
You may want to check audio ADCs and DACs for example, which--- Synchronet 3.21d-Linux NewsLink 1.2
have atrocious accuracy, but excellent resolution. An example
of the opposite might be a voltage reference, which has excellent
accuracy, but no resolution at all.
Of course in general, there is a tendency of accurate instruments
to have a better resolution too.
I just bought an amp clamp meter, and it states the error is "+/-
1.9% + 3 digits". What does the "3 digits" part mean?
On Thu, 18 Jun 2020 15:38:46 +0100, Pimpom <nobody@nowhere.com> wrote:
On 6/18/2020 6:33 PM, Commander Kinsey wrote:
I just bought an amp clamp meter, and it states the error is "+/-
1.9% + 3 digits". What does the "3 digits" part mean?
If your meter should read, say 1.875 A, the correct reading could
be anywhere from 1.872 to 1.878. This is a possible error in the
display presented to you in the analog-digital display conversion
process. The +/-1.9% possible error is about the measurement
taken including - but not only - any error made by the sensor.
Thanks, I wonder why all my other meters only list a % error. Is it included within it somehow, or are they just lying, or do some meters
not have this error?
On 6/20/2020 4:29 AM, Commander Kinsey wrote:
On Fri, 19 Jun 2020 23:55:42 +0100, Ralph Mowery <rmowery28146@earthlink.net> wrote:
In article <op.0mg7zmz6wdg98l@glass>, CFKinsey@military.org.jp says...
But what I'm surprised at is a ?5 multimeter (not clamp) not giving a digits error. Maybe precision on a simple voltmeter is cheap as chips nowadays?
You have to be careful how you throw precision and accurecy around.
A meter that shows 4 digits is more precice than one that shows only 3
digits, however the 4 digit one may only be 1% accurate and the 3 digit
one may be .5% accurate.
It is easy to get precision, but difficule to be accurate. Think of it
as shooting a gun. Precision may be how close the bullets land to each
other where ever they land on the target, but to be accurate the bullets >>> have to land on the center of the target. Such as all the bullets could >>> land very close to each other, but not even hit the target.
As I mentioned, a good meter will not have a digits error outside the +- >>> one digit due to rounding.
That didn't help. I interchange the two. I just want to know how close to the correct reading the readout is. Adding another digit doesn't improve anything if it's incorrect. And shooting all the bullets in one place doesn't help if they all miss.
Take pi as an example. It can be said that 3.14 is accurate as a
three-digit value, but 3.1416 is more precise because it has a
higher resolution.
OTOH, deriving it from 22/7 or 3.1429 has the same 5-digit
resolution and is just as precise as far as the number it
represents is concerned but is less accurate.
In this particular case, 3.1416 is both more precise and more
accurate than 3.14 but that's not always the case with measurements.
My mechanical slide caliper has a resolution of 0.001 inch. This
means that it can display measurements with a precision of 1 mil,
but that doesn't guarantee that a measurement taken with it will
be accurate to 1 mil. I may not always press the jaws snugly
enough and the scale may not be perfectly accurate.
On Sat, 20 Jun 2020 16:24:41 +0100, Ralph Mowery <rmowery28146@earthlink.net> wrote:
In article <op.0miefkhkwdg98l@glass>, CFKinsey@military.org.jp says...
I'd need to contract OCD to understand that. There's only one thing in question here, how close is the reading to the correct value. You can't split that into two. 3.1416 is better than 3.14, and that's it. All you can state with a reading is it's correct to within a certain percentage.
Try this.
A doctor does a very complicated operation on your left arm like a joint
replacement. It all goes very well. Very precise.
However he should have done the operation on the right arm that was
causing trouble. Not accurate.
Nope, because the first one is 100% useless. I wouldn't call that precise at all, as he was out by half a metre.
That is why a voltmeter can show 3 digits and be accurate to only the
last digit being in question by one number either way, but a 5 digit
volt meter can show many numbers, but if it is not calibrated corrctly
the 2nd digit to the 5 th digit could be way off and the meter not
accurate at all.
Showing those extra two numbers is pointless if they're wrong. All that matters is how many volts difference between the actual voltage and what is shown.
In article <U6sHG.61028$Nj4.43851@fx24.ams1>, nobody@nowhere.com says...
You keep saying that it's only the accuracy that matters. That's
true to some - and only some - extent.
Sometimes it is precision.
I worked at a company making polyester from raw materials. In a room
was a panel with about 10 temperature gauges. At a certain time all
gauges were marked and a sample of the material was sent to the lab. If
it came back good, then the object was to keep all the gauges on the
mark. It did not matter how far off the gauges were from the actual temperature. No mater how well we calibrated the guages there were
several other factors that we had no control over. Such as the
thermocouples they were connected to. The specifications were +- 3 deg
C. on the thermocouples from the factory. If the temperature varied
more than 1 deg C at 300 deg C it could mess up the material.
So the object was precision and not accuracy.
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
My mechanical slide caliper has a resolution of 0.001 inch. This
means that it can display measurements with a precision of 1 mil,
What if your caliper had a resolution of 1 mil +/- 3 counts on the last digit? That's the issue with multimeters that have completely bogus digits
at the end. Those number are just noise and serve no purpose at all. They don't even compare to all bullets missing the target but landing in the
same wrong spot.
but that doesn't guarantee that a measurement taken with it will
be accurate to 1 mil. I may not always press the jaws snugly
enough and the scale may not be perfectly accurate.
So the object was precision and not accuracy.
If the goal was keep the needle on their marks it does't have to mean anything was precise. Maybe your guages had no faces, or read mA instead
of degrees, and bent needles. As long as your +/- 3 degree thermocouples
and controllers did not jump up and down + and then -3 degrees all the
time, you were good.
In article <rd400g$egj$2@reader1.panix.com>, presence@MUNGEpanix.com
says...
So the object was precision and not accuracy.
If the goal was keep the needle on their marks it does't have to mean
anything was precise. Maybe your guages had no faces, or read mA instead
of degrees, and bent needles. As long as your +/- 3 degree thermocouples
and controllers did not jump up and down + and then -3 degrees all the
time, you were good.
One good example of what we had is this.
In a vat of material is a test hole. In that hole is a rod about 3/8
inch in diameter and a foot long. At the end there are two
thermocouples and two RTDs. The thermocouples wires go about 100 feet
to a PLC (similar to a computer) card that converts the milivolts to
digital that is then displayed on a compute screen. The RTDs go about
10 feet to a converter that converts the change in resistance to a 4 to
20 miliamp signal. That goes to a card on the PLC and then to the
computer display.
While the computer will display to 3 decimal places at 300 deg C from
the lowest to the highest temperature shown on the display can be around
3 deg differnet and all 3 be within the limits of the equipmnet.
At a certain time a sample is sent to the lab and one of the computer displays is set as a standard and the object of the PLC is to keep the actual temperature , whatever it actually is, to that 'standard'. Not
too accurate as to temperature, but very precice. The operators only
needed to keep that one computer display as close to that 'mark' as they
can if for some reason the PLC messes up and they have to adjust the control manual.
On 6/26/2020 9:53 AM, Cydrome Leader wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:You seem intent on picking an argument by inserting a statement
My mechanical slide caliper has a resolution of 0.001 inch. This
means that it can display measurements with a precision of 1 mil,
What if your caliper had a resolution of 1 mil +/- 3 counts on the last
digit? That's the issue with multimeters that have completely bogus digits >> at the end. Those number are just noise and serve no purpose at all. They
don't even compare to all bullets missing the target but landing in the
same wrong spot.
that agrees with the following sentences. BTW, my caliper is not
digital, so the matter of +/- count is irrelevant.
but that doesn't guarantee that a measurement taken with it will
be accurate to 1 mil. I may not always press the jaws snugly
enough and the scale may not be perfectly accurate.
What's the control loop if the PLC dies? How do people control temperatures manually? Is there a foot pedal to stomp on to switch the heaters on and off?
In article <rd6pl5$42t$1@reader1.panix.com>, presence@MUNGEpanix.com
says...
What's the control loop if the PLC dies? How do people control temperatures >> manually? Is there a foot pedal to stomp on to switch the heaters on and
off?
The process has two PLCs running all the time. There are two or more computers hooked to the data stream for the PLCs One PLC is the so
called hot backup. It is not controlling, but if the primary one quits,
the secondary one will either switch over automatically or it can be manually switched.
One thermocouple is connected to the control loop. If that TC goes bad, there are other TCs that give the temperature readout and the operators switch the control screen for that temperature to manual and they have
to keep an eye on it and manually enter on the computer keyboard what percentage of valve opening is needed to mantain the correct
temperature.
OK, so if a PLC croaks, the operators can switch to the redundant one. If a probe of whatever you have between it and the current loop or whatever it was fails, it's 100% manual control? How do you share the reading from one problem? Not trying to pole holes in theory here, just actually curious.
One thing annoying about the probes I deal with is it seems no two are alike. Never been able to swap one for another, even with short leads, even with three lead compensation and get the same behavior on the same controller.
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Thu, 18 Jun 2020 15:38:46 +0100, Pimpom <nobody@nowhere.com> wrote:
On 6/18/2020 6:33 PM, Commander Kinsey wrote:
I just bought an amp clamp meter, and it states the error is "+/-
1.9% + 3 digits". What does the "3 digits" part mean?
If your meter should read, say 1.875 A, the correct reading could
be anywhere from 1.872 to 1.878. This is a possible error in the
display presented to you in the analog-digital display conversion
process. The +/-1.9% possible error is about the measurement
taken including - but not only - any error made by the sensor.
Thanks, I wonder why all my other meters only list a % error. Is it
included within it somehow, or are they just lying, or do some meters
not have this error?
One generally finds the percentage plus digits error measures on more expensive equipment. Less expensive equipment more often than not only
lists a percentage and nothing more.
In article <rdblel$f8m$5@reader1.panix.com>, presence@MUNGEpanix.com
says...
OK, so if a PLC croaks, the operators can switch to the redundant one. If a >> probe of whatever you have between it and the current loop or whatever it >> was fails, it's 100% manual control? How do you share the reading from one >> problem? Not trying to pole holes in theory here, just actually curious.
One thing annoying about the probes I deal with is it seems no two are
alike. Never been able to swap one for another, even with short leads, even >> with three lead compensation and get the same behavior on the same
controller.
Here is sort of how it works. One PLC quits. The second PLC takes over automatically or can be switched manually at any time.
A TC feeding the PLCs fails. An alarm is sounded as the PLC thinks the process has gone out of limits. The operator is at a computer (was
running a graphics program on Win XP when I left) , He calls up the
control screen and puts the control in manual and sets the signal to the valve to where it was before the device fails. There is a secondary temperature TC. The operator looks back in the history of the read outs
and sees that the primary control TC was showing 300.2 deg C when the
lab said the process was on target. At the same time the secondary TC
was showing 301.6 deg C. So the operator now has the control in manual
and adjusts the output of the contoler to try and keep the process at
301.6 deg C showing on the readiout now.
When the bad TC is replaced and the process is checked out by the lab,
The new setting may come back as 301.1 deg C. So that will be the new target.
The vessels are large enough , around 10 feet tall and 5 feet in
diameter so the temperature change takes a long time.
The process is making polyester material. We put in a powder that looks like flour and a liquid Glycol. It is heated to about 300 deg C. There
are 5 vessels in the process and it is continious. The powder and
liquid are put in the first vessel and at the bottom is a pipe that
conveys it to the next one. The process is repeated and small ammouts
of other chemicals are added at each stage. It is extruded after the
last vessel to what looks like string.
It takes about 15 hours for the material to make it from start to
finish. We make about 3000 pounds to 10,000 pounds of material each
hour depending on the size of the process line.
About 2 years ago the plant that had around 3000 people 20 years ago
went out of business. Mostly because of other countries makeing the material much cheaper.
On Wed, 24 Jun 2020 21:06:04 +0100, Rich <rich@example.invalid> wrote:
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Thu, 18 Jun 2020 15:38:46 +0100, Pimpom <nobody@nowhere.com> wrote:
On 6/18/2020 6:33 PM, Commander Kinsey wrote:
I just bought an amp clamp meter, and it states the error is "+/-
1.9% + 3 digits". What does the "3 digits" part mean?
If your meter should read, say 1.875 A, the correct reading could
be anywhere from 1.872 to 1.878. This is a possible error in the
display presented to you in the analog-digital display conversion
process. The +/-1.9% possible error is about the measurement
taken including - but not only - any error made by the sensor.
Thanks, I wonder why all my other meters only list a % error. Is it
included within it somehow, or are they just lying, or do some meters
not have this error?
One generally finds the percentage plus digits error measures on more
expensive equipment. Less expensive equipment more often than not only
lists a percentage and nothing more.
So should I assume the cheaper ones are lying? Or have they just made a rough estimate adding the two errors?
On Wed, 24 Jun 2020 21:06:04 +0100, Rich <rich@example.invalid> wrote:
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Thu, 18 Jun 2020 15:38:46 +0100, Pimpom <nobody@nowhere.com> wrote:
On 6/18/2020 6:33 PM, Commander Kinsey wrote:
I just bought an amp clamp meter, and it states the error is "+/-
1.9% + 3 digits". What does the "3 digits" part mean?
If your meter should read, say 1.875 A, the correct reading could
be anywhere from 1.872 to 1.878. This is a possible error in the
display presented to you in the analog-digital display conversion
process. The +/-1.9% possible error is about the measurement
taken including - but not only - any error made by the sensor.
Thanks, I wonder why all my other meters only list a % error. Is
it included within it somehow, or are they just lying, or do some
meters not have this error?
One generally finds the percentage plus digits error measures on
more expensive equipment. Less expensive equipment more often than
not only lists a percentage and nothing more.
So should I assume the cheaper ones are lying?
Or have they just made a rough estimate adding the two errors?
So should I assume the cheaper ones are lying? Or have they just made a rough estimate adding the two errors?
might be both. I dug out my first DMM, a Wavetek DM2, circa 1990s. It might have been from a raffle or something like that.
The DC voltage specs range from 0.8% +1 digit (not bad really) over to the AC ranges which are "1.2% RDG +10 Digits". If I had new leads, I'd trust it with outlet voltage, but would stay away from 208volts. The meter has 3.5 digits or max display of 1999. I'm figuring a real 100volt AC reading could be 99 to 101 plus another error of +/- 1 volt for the 10 digits tolerance
on the display or count. so 100volts from your Japanese outlet reference might read 98 to 102 volts. So while in the ballpark, it's better than you can read off a Simpson 260 meter in the AC voltage range. I could be wrong on this too.
It's a pretty decent meter for poking at DC circuits for the tens of
dollars is must have cost when new.
In article <rdecuc$m73$1@reader1.panix.com>, presence@MUNGEpanix.com
says...
So should I assume the cheaper ones are lying? Or have they just made a rough estimate adding the two errors?
might be both. I dug out my first DMM, a Wavetek DM2, circa 1990s. It might >> have been from a raffle or something like that.
The DC voltage specs range from 0.8% +1 digit (not bad really) over to the >> AC ranges which are "1.2% RDG +10 Digits". If I had new leads, I'd trust it >> with outlet voltage, but would stay away from 208volts. The meter has 3.5 >> digits or max display of 1999. I'm figuring a real 100volt AC reading could >> be 99 to 101 plus another error of +/- 1 volt for the 10 digits tolerance >> on the display or count. so 100volts from your Japanese outlet reference
might read 98 to 102 volts. So while in the ballpark, it's better than you >> can read off a Simpson 260 meter in the AC voltage range. I could be wrong >> on this too.
It's a pretty decent meter for poking at DC circuits for the tens of
dollars is must have cost when new.
It seems that maybe due to modern manufactoring the meters are more
accurate than they were 20 years ago. I bought some DC voltmeters from China. They display 3 digits. They read from 0 to 99.9 volts. I coulg
get 4 of them for less than $ 15 including the shipping. I hooked all 4
of them in parallel with a Fluke 87 . Three of them tracked right along with the Fluke with the last digit sometimes being one high or low from
0 to 24 volts. The fourth one was off by an average of 2 on the last
digit. I found an adjustment screw on the back of the meter and tweaked
it and re ran the test. It then fell in line with the other meters.
I had 3 or 4 of the Harbor Freight 'free' multimeters. The ones that usually sell for around $ 5. They seem to be reasonable accurate for
the money. Plenty accurate for the home user to test things around the house. I do admit that the safety issue of putting them across the 120
or 240 volt power wires is somewhat doubtful. I sure would not use one where I worked to put across the 480 volt 3 phase system that is fused
with 200 amps.
In sci.electronics.equipment Ralph Mowery <rmowery28146@earthlink.net> wrote:
In article <rdecuc$m73$1@reader1.panix.com>, presence@MUNGEpanix.com
says...
So should I assume the cheaper ones are lying? Or have they just made a rough estimate adding the two errors?
might be both. I dug out my first DMM, a Wavetek DM2, circa 1990s. It might
have been from a raffle or something like that.
The DC voltage specs range from 0.8% +1 digit (not bad really) over to the
AC ranges which are "1.2% RDG +10 Digits". If I had new leads, I'd trust it
with outlet voltage, but would stay away from 208volts. The meter has 3.5 >>> digits or max display of 1999. I'm figuring a real 100volt AC reading could
be 99 to 101 plus another error of +/- 1 volt for the 10 digits tolerance >>> on the display or count. so 100volts from your Japanese outlet reference >>> might read 98 to 102 volts. So while in the ballpark, it's better than you >>> can read off a Simpson 260 meter in the AC voltage range. I could be wrong >>> on this too.
It's a pretty decent meter for poking at DC circuits for the tens of
dollars is must have cost when new.
It seems that maybe due to modern manufactoring the meters are more
accurate than they were 20 years ago. I bought some DC voltmeters from
China. They display 3 digits. They read from 0 to 99.9 volts. I coulg
get 4 of them for less than $ 15 including the shipping. I hooked all 4
of them in parallel with a Fluke 87 . Three of them tracked right along
with the Fluke with the last digit sometimes being one high or low from
0 to 24 volts. The fourth one was off by an average of 2 on the last
digit. I found an adjustment screw on the back of the meter and tweaked
it and re ran the test. It then fell in line with the other meters.
Have you run this test with AC? That seems to be where the wheels come
off. I brought up this thread to a friend and he mentioned his quest to repair some sort of HP true RMS meter that uses a thermocouple and heater
to properly measure complex waveforms. I can't even guess how slow such a meter might be.
Have you run this test with AC? That seems to be where the wheels come
off. I brought up this thread to a friend and he mentioned his quest to repair some sort of HP true RMS meter that uses a thermocouple and heater
to properly measure complex waveforms. I can't even guess how slow such a meter might be.
I had 3 or 4 of the Harbor Freight 'free' multimeters. The ones that usually sell for around $ 5. They seem to be reasonable accurate for
the money. Plenty accurate for the home user to test things around the house. I do admit that the safety issue of putting them across the 120
or 240 volt power wires is somewhat doubtful. I sure would not use one where I worked to put across the 480 volt 3 phase system that is fused with 200 amps.
I'm pretty timid with anything upstream from a plain outlet. I had an
edison base fuse burst in my hand once. Never seen one come apart before.
It was just a 120v lighting circuit, but right off the service panel. There's way more excitement near those things.
In article <rdjsa6$28b$1@reader1.panix.com>, presence@MUNGEpanix.com
says...
Have you run this test with AC? That seems to be where the wheels come
off. I brought up this thread to a friend and he mentioned his quest to
repair some sort of HP true RMS meter that uses a thermocouple and heater
to properly measure complex waveforms. I can't even guess how slow such a
meter might be.
I had 3 or 4 of the Harbor Freight 'free' multimeters. The ones that
usually sell for around $ 5. They seem to be reasonable accurate for
the money. Plenty accurate for the home user to test things around the
house. I do admit that the safety issue of putting them across the 120
or 240 volt power wires is somewhat doubtful. I sure would not use one
where I worked to put across the 480 volt 3 phase system that is fused
with 200 amps.
I'm pretty timid with anything upstream from a plain outlet. I had an
edison base fuse burst in my hand once. Never seen one come apart before.
It was just a 120v lighting circuit, but right off the service panel.
There's way more excitement near those things.
I have not ran any tests for AC . The things I work with don't care
about very much about being accurate to more than around 5 %. Usually
it is more of do I have a voltage/current or not.
When I work on most anything other than low voltage (below 100 volts) I
ues either my Simpson 260 analog meter or a Fluke meter that is rated
for cat 3 and 4. If you have not heard of the Cat numbers, they are for devices used in different power circuits. I don't know the numbers off
hand, but it goes something like this, Cat 1 is for low voltage items,
Cat 2 for things like stoves and refrigerators, Cat 3 for homw
wiring,and Cat 4 for the very high power circuits like I often worked on
like the 480 volt AC and 300 amps.
For a real scare you should see some of the safety movies that Fluke put
out. They show under test conditions what can hapen to inexpensive
meters and their meters under different conditions like having the
meter set for amps and putting across a 480 volt circuit that has plenty
of amps .
In article <rdjsa6$28b$1@reader1.panix.com>, presence@MUNGEpanix.com
says...
Have you run this test with AC? That seems to be where the wheels come
off. I brought up this thread to a friend and he mentioned his quest to
repair some sort of HP true RMS meter that uses a thermocouple and heater >> to properly measure complex waveforms. I can't even guess how slow such a >> meter might be.
I had 3 or 4 of the Harbor Freight 'free' multimeters. The ones that
usually sell for around $ 5. They seem to be reasonable accurate for
the money. Plenty accurate for the home user to test things around the >> > house. I do admit that the safety issue of putting them across the 120 >> > or 240 volt power wires is somewhat doubtful. I sure would not use one >> > where I worked to put across the 480 volt 3 phase system that is fused >> > with 200 amps.
I'm pretty timid with anything upstream from a plain outlet. I had an
edison base fuse burst in my hand once. Never seen one come apart before. >> It was just a 120v lighting circuit, but right off the service panel.
There's way more excitement near those things.
I have not ran any tests for AC . The things I work with don't care
about very much about being accurate to more than around 5 %. Usually
it is more of do I have a voltage/current or not.
When I work on most anything other than low voltage (below 100 volts) I
ues either my Simpson 260 analog meter or a Fluke meter that is rated
for cat 3 and 4. If you have not heard of the Cat numbers, they are for devices used in different power circuits. I don't know the numbers off hand, but it goes something like this, Cat 1 is for low voltage items,
Cat 2 for things like stoves and refrigerators, Cat 3 for homw
wiring,and Cat 4 for the very high power circuits like I often worked on like the 480 volt AC and 300 amps.
For a real scare you should see some of the safety movies that Fluke put out. They show under test conditions what can hapen to inexpensive
meters and their meters under different conditions like having the
meter set for amps and putting across a 480 volt circuit that has plenty
of amps .
I have not ran any tests for AC . The things I work with don't care
about very much about being accurate to more than around 5 %. Usually
it is more of do I have a voltage/current or not.
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Sat, 20 Jun 2020 16:24:41 +0100, Ralph Mowery <rmowery28146@earthlink.net> wrote:
In article <op.0miefkhkwdg98l@glass>, CFKinsey@military.org.jp says...
I'd need to contract OCD to understand that. There's only one thing in question here, how close is the reading to the correct value. You can't split that into two. 3.1416 is better than 3.14, and that's it. All you can state with a reading is it's correct to within a certain percentage.
Try this.
A doctor does a very complicated operation on your left arm like a joint >>> replacement. It all goes very well. Very precise.
However he should have done the operation on the right arm that was
causing trouble. Not accurate.
Nope, because the first one is 100% useless. I wouldn't call that precise at all, as he was out by half a metre.
That is why a voltmeter can show 3 digits and be accurate to only the
last digit being in question by one number either way, but a 5 digit
volt meter can show many numbers, but if it is not calibrated corrctly
the 2nd digit to the 5 th digit could be way off and the meter not
accurate at all.
Showing those extra two numbers is pointless if they're wrong. All that matters is how many volts difference between the actual voltage and what is shown.
agreed. The problem with the bullets and the target story is that when explained, we somehow perfectly know where the bullets are- be in on
target or a small grouping somewhere else. Cheapo meters won't give CONSISTENT or REPEATABLE results, not matter how "precise" they pretended
to be, or how accurate the spec sheet claims, especially considering the
last digit(s) may be totaly wrong, and random. It's like having crappy or dirty test leads or a component. You'll get all the digits in the world,
but they keep changing. You won't even be able to pick a reading.
Keep in mind that "calibrated" equipment doesn't even have to be precise
or accurate. An example would be an adjustable power supply with digital readout. Say it's always reads high by 0.7 volts. It's not precise or accurate, but by knowing the offset it can used with success and may even have great regulation.
On the other hand say you have an alibaba special power supply that's "accurate" to +/- 0.35 volts, with terrible regulation that oscillates.
What power supply is better?
So the point is cheapo equipment can have lots of bogus digits and
readings that flop up and down, while better equipment can be more consistently wrong, which can be compensated for. Precision and accuracy
mean little by themselves if you need multiple readings.
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
On 6/20/2020 4:29 AM, Commander Kinsey wrote:
On Fri, 19 Jun 2020 23:55:42 +0100, Ralph Mowery <rmowery28146@earthlink.net> wrote:
In article <op.0mg7zmz6wdg98l@glass>, CFKinsey@military.org.jp says... >>>>>
But what I'm surprised at is a ?5 multimeter (not clamp) not giving a digits error. Maybe precision on a simple voltmeter is cheap as chips nowadays?
You have to be careful how you throw precision and accurecy around.
A meter that shows 4 digits is more precice than one that shows only 3 >>>> digits, however the 4 digit one may only be 1% accurate and the 3 digit >>>> one may be .5% accurate.
It is easy to get precision, but difficule to be accurate. Think of it >>>> as shooting a gun. Precision may be how close the bullets land to each >>>> other where ever they land on the target, but to be accurate the bullets >>>> have to land on the center of the target. Such as all the bullets could >>>> land very close to each other, but not even hit the target.
As I mentioned, a good meter will not have a digits error outside the +- >>>> one digit due to rounding.
That didn't help. I interchange the two. I just want to know how close to the correct reading the readout is. Adding another digit doesn't improve anything if it's incorrect. And shooting all the bullets in one place doesn't help if they all miss.
Take pi as an example. It can be said that 3.14 is accurate as a
three-digit value, but 3.1416 is more precise because it has a
higher resolution.
OTOH, deriving it from 22/7 or 3.1429 has the same 5-digit
resolution and is just as precise as far as the number it
represents is concerned but is less accurate.
In this particular case, 3.1416 is both more precise and more
accurate than 3.14 but that's not always the case with measurements.
My mechanical slide caliper has a resolution of 0.001 inch. This
means that it can display measurements with a precision of 1 mil,
What if your caliper had a resolution of 1 mil +/- 3 counts on the last digit? That's the issue with multimeters that have completely bogus digits
at the end. Those number are just noise and serve no purpose at all. They don't even compare to all bullets missing the target but landing in the
same wrong spot.
but that doesn't guarantee that a measurement taken with it will
be accurate to 1 mil. I may not always press the jaws snugly
enough and the scale may not be perfectly accurate.
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com> wrote:.....<snip>........
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
My mechanical slide caliper has a resolution of 0.001 inch. This
means that it can display measurements with a precision of 1 mil,
What if your caliper had a resolution of 1 mil +/- 3 counts on the last
digit?
In America, what is a "mill"? In the UK, it used to mean a thousandth of an inch, but people use it to mean a millimetre nowadays.
On 7/12/2020 11:15 PM, Commander Kinsey wrote:
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com>
wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
.....<snip>........My mechanical slide caliper has a resolution of 0.001 inch. This
means that it can display measurements with a precision of 1 mil,
What if your caliper had a resolution of 1 mil +/- 3 counts on the last
digit?
In America, what is a "mill"?a In the UK, it used to mean a thousandth of an
inch, but people use it to mean a millimetre nowadays.
It's not a mill. It's mil - single l. It means, and has always meant, a thousandth of an inch. It's not an Americanism.
On Fri, 26 Jun 2020 05:54:19 +0100, Cydrome Leader <presence@mungepanix.com> wrote:
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Sat, 20 Jun 2020 16:24:41 +0100, Ralph Mowery <rmowery28146@earthlink.net> wrote:
In article <op.0miefkhkwdg98l@glass>, CFKinsey@military.org.jp says... >>>>>
I'd need to contract OCD to understand that. There's only one thing in question here, how close is the reading to the correct value. You can't split that into two. 3.1416 is better than 3.14, and that's it. All you can state with a reading is it's correct to within a certain percentage.
Try this.
A doctor does a very complicated operation on your left arm like a joint >>>> replacement. It all goes very well. Very precise.
However he should have done the operation on the right arm that was
causing trouble. Not accurate.
Nope, because the first one is 100% useless. I wouldn't call that precise at all, as he was out by half a metre.
That is why a voltmeter can show 3 digits and be accurate to only the
last digit being in question by one number either way, but a 5 digit
volt meter can show many numbers, but if it is not calibrated corrctly >>>> the 2nd digit to the 5 th digit could be way off and the meter not
accurate at all.
Showing those extra two numbers is pointless if they're wrong. All that matters is how many volts difference between the actual voltage and what is shown.
agreed. The problem with the bullets and the target story is that when
explained, we somehow perfectly know where the bullets are- be in on
target or a small grouping somewhere else. Cheapo meters won't give
CONSISTENT or REPEATABLE results, not matter how "precise" they pretended
to be, or how accurate the spec sheet claims, especially considering the
last digit(s) may be totaly wrong, and random. It's like having crappy or
dirty test leads or a component. You'll get all the digits in the world,
but they keep changing. You won't even be able to pick a reading.
Keep in mind that "calibrated" equipment doesn't even have to be precise
or accurate. An example would be an adjustable power supply with digital
readout. Say it's always reads high by 0.7 volts. It's not precise or
accurate, but by knowing the offset it can used with success and may even
have great regulation.
I've got thermostats like that, I've calibrated them to 0.1C. Trouble
is, they have remote sensors which work perfectly, but if the actual
unit gets very warm (as in direct sunlight), the reading goes up by as
much as 2C. Nevermind, they happen to be in my conservatory (the main source of heat in the summer), along with the air conditioner, so on a
hot day they switch it on slightly too soon, then correct themselves
when the AC cools them off.
On 12/07/20 19:01, Pimpom wrote:
On 7/12/2020 11:15 PM, Commander Kinsey wrote:
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com>.....<snip>........
wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
My mechanical slide caliper has a resolution of 0.001 inch. This
means that it can display measurements with a precision of 1 mil,
What if your caliper had a resolution of 1 mil +/- 3 counts on the last >>>> digit?
In America, what is a "mill"?a In the UK, it used to mean a thousandth of an
inch, but people use it to mean a millimetre nowadays.
It's not a mill. It's mil - single l. It means, and has always meant, a
thousandth of an inch. It's not an Americanism.
In the UK "mill" means millilitre.
If you want to refer to fractions of an inch, then
it is /always/ "thou", i.e. thousandths of an inch.
In the UK "mil/mill" /never/ means 0.001".
In sci.electronics.basics Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Fri, 26 Jun 2020 05:54:19 +0100, Cydrome Leader <presence@mungepanix.com> wrote:
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Sat, 20 Jun 2020 16:24:41 +0100, Ralph Mowery <rmowery28146@earthlink.net> wrote:
In article <op.0miefkhkwdg98l@glass>, CFKinsey@military.org.jp says... >>>>>>
I'd need to contract OCD to understand that. There's only one thing in question here, how close is the reading to the correct value. You can't split that into two. 3.1416 is better than 3.14, and that's it. All you can state with a reading is it's correct to within a certain percentage.
Try this.
A doctor does a very complicated operation on your left arm like a joint >>>>> replacement. It all goes very well. Very precise.
However he should have done the operation on the right arm that was
causing trouble. Not accurate.
Nope, because the first one is 100% useless. I wouldn't call that precise at all, as he was out by half a metre.
That is why a voltmeter can show 3 digits and be accurate to only the >>>>> last digit being in question by one number either way, but a 5 digit >>>>> volt meter can show many numbers, but if it is not calibrated corrctly >>>>> the 2nd digit to the 5 th digit could be way off and the meter not
accurate at all.
Showing those extra two numbers is pointless if they're wrong. All that matters is how many volts difference between the actual voltage and what is shown.
agreed. The problem with the bullets and the target story is that when
explained, we somehow perfectly know where the bullets are- be in on
target or a small grouping somewhere else. Cheapo meters won't give
CONSISTENT or REPEATABLE results, not matter how "precise" they pretended >>> to be, or how accurate the spec sheet claims, especially considering the >>> last digit(s) may be totaly wrong, and random. It's like having crappy or >>> dirty test leads or a component. You'll get all the digits in the world, >>> but they keep changing. You won't even be able to pick a reading.
Keep in mind that "calibrated" equipment doesn't even have to be precise >>> or accurate. An example would be an adjustable power supply with digital >>> readout. Say it's always reads high by 0.7 volts. It's not precise or
accurate, but by knowing the offset it can used with success and may even >>> have great regulation.
I've got thermostats like that, I've calibrated them to 0.1C. Trouble
is, they have remote sensors which work perfectly, but if the actual
unit gets very warm (as in direct sunlight), the reading goes up by as
much as 2C. Nevermind, they happen to be in my conservatory (the main
source of heat in the summer), along with the air conditioner, so on a
hot day they switch it on slightly too soon, then correct themselves
when the AC cools them off.
Is it the controller that's off by 2C when it warms up?
On 12/07/20 19:01, Pimpom wrote:
On 7/12/2020 11:15 PM, Commander Kinsey wrote:
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com>.....<snip>........
wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
My mechanical slide caliper has a resolution of 0.001 inch. This
means that it can display measurements with a precision of 1 mil,
What if your caliper had a resolution of 1 mil +/- 3 counts on the last >>>> digit?
In America, what is a "mill"? In the UK, it used to mean a thousandth of an
inch, but people use it to mean a millimetre nowadays.
It's not a mill. It's mil - single l. It means, and has always meant, a
thousandth of an inch. It's not an Americanism.
In the UK "mill" means millilitre.
If you want to refer to fractions of an inch, then
it is /always/ "thou", i.e. thousandths of an inch.
In the UK "mil/mill" /never/ means 0.001".
On 7/13/2020 12:51 AM, Tom Gardner wrote:
On 12/07/20 19:01, Pimpom wrote:
On 7/12/2020 11:15 PM, Commander Kinsey wrote:
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com>.....<snip>........
wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
My mechanical slide caliper has a resolution of 0.001 inch. This
means that it can display measurements with a precision of 1 mil,
What if your caliper had a resolution of 1 mil +/- 3 counts on the last >>>>> digit?
In America, what is a "mill"? In the UK, it used to mean a thousandth of an
inch, but people use it to mean a millimetre nowadays.
It's not a mill. It's mil - single l. It means, and has always meant, a
thousandth of an inch. It's not an Americanism.
In the UK "mill" means millilitre.
If you want to refer to fractions of an inch, then
it is /always/ "thou", i.e. thousandths of an inch.
In the UK "mil/mill" /never/ means 0.001".
My bad. This is the first time I heard that the mil is not used
as the unit for .001" in the UK. (I'm *not* an American).
On 7/12/2020 11:15 PM, Commander Kinsey wrote:
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com> wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
.....<snip>........My mechanical slide caliper has a resolution of 0.001 inch. This
means that it can display measurements with a precision of 1 mil,
What if your caliper had a resolution of 1 mil +/- 3 counts on the last
digit?
In America, what is a "mill"? In the UK, it used to mean a thousandth of an inch, but people use it to mean a millimetre nowadays.
It's not a mill. It's mil - single l. It means, and has always
meant, a thousandth of an inch. It's not an Americanism.
On Mon, 13 Jul 2020 05:53:29 +0100, Pimpom <nobody@nowhere.com> wrote:
On 7/13/2020 12:51 AM, Tom Gardner wrote:
On 12/07/20 19:01, Pimpom wrote:
On 7/12/2020 11:15 PM, Commander Kinsey wrote:
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com>.....<snip>........
wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
My mechanical slide caliper has a resolution of 0.001 inch. This >>>>>>> means that it can display measurements with a precision of 1 mil, >>>>>>What if your caliper had a resolution of 1 mil +/- 3 counts on the last >>>>>> digit?
In America, what is a "mill"? In the UK, it used to mean a thousandth of an
inch, but people use it to mean a millimetre nowadays.
It's not a mill. It's mil - single l. It means, and has always meant, a >>>> thousandth of an inch. It's not an Americanism.
In the UK "mill" means millilitre.
If you want to refer to fractions of an inch, then
it is /always/ "thou", i.e. thousandths of an inch.
In the UK "mil/mill" /never/ means 0.001".
My bad. This is the first time I heard that the mil is not used
as the unit for .001" in the UK. (I'm *not* an American).
If you're not American why did you say "my bad"? Your bad what? Finish the sentence!
On 7/13/2020 6:06 PM, Commander Kinsey wrote:[...]
If you're not American why did you say "my bad"?a Your bad what?So now you're a grammar Nazi? This after I (and others) spent
Finish the sentence!
considerable time and effort[...]
On 2020-07-13 17:27, Pimpom wrote:
On 7/13/2020 6:06 PM, Commander Kinsey wrote:[...]
If you're not American why did you say "my bad"?a Your bad what? Finish theSo now you're a grammar Nazi? This after I (and others) spent considerable >> time and effort[...]
sentence!
Just drop it. There are better things to do than to argue
with a cantankerous teenager. If a conversation turns into
a source of irritation, the best way is to simply drop out.
On Sun, 12 Jul 2020 20:21:10 +0100, Tom Gardner <spamjunk@blueyonder.co.uk> wrote:
On 12/07/20 19:01, Pimpom wrote:
On 7/12/2020 11:15 PM, Commander Kinsey wrote:
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com>.....<snip>........
wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
My mechanical slide caliper has a resolution of 0.001 inch. This
means that it can display measurements with a precision of 1 mil,
What if your caliper had a resolution of 1 mil +/- 3 counts on the last >>>>> digit?
In America, what is a "mill"? In the UK, it used to mean a thousandth of an
inch, but people use it to mean a millimetre nowadays.
It's not a mill. It's mil - single l. It means, and has always meant, a
thousandth of an inch. It's not an Americanism.
In the UK "mill" means millilitre.
If you want to refer to fractions of an inch, then
it is /always/ "thou", i.e. thousandths of an inch.
In the UK "mil/mill" /never/ means 0.001".
Yes it does. My neighbour's a tradesman (in Scotland) and says
"mill/mil" (I don't know which as they sound the same in speech) as shorthand for millimetre. As in "that kitchen unit is 600 mill wide". Since we don't use inches for such things in the UK, there's no
confusion.
In article <rdecuc$m73$1@reader1.panix.com>, presence@MUNGEpanix.com
says...
So should I assume the cheaper ones are lying? Or have they just made a rough estimate adding the two errors?
might be both. I dug out my first DMM, a Wavetek DM2, circa 1990s. It might >> have been from a raffle or something like that.
The DC voltage specs range from 0.8% +1 digit (not bad really) over to the >> AC ranges which are "1.2% RDG +10 Digits". If I had new leads, I'd trust it >> with outlet voltage, but would stay away from 208volts. The meter has 3.5
digits or max display of 1999. I'm figuring a real 100volt AC reading could >> be 99 to 101 plus another error of +/- 1 volt for the 10 digits tolerance
on the display or count. so 100volts from your Japanese outlet reference
might read 98 to 102 volts. So while in the ballpark, it's better than you >> can read off a Simpson 260 meter in the AC voltage range. I could be wrong >> on this too.
It's a pretty decent meter for poking at DC circuits for the tens of
dollars is must have cost when new.
It seems that maybe due to modern manufactoring the meters are more
accurate than they were 20 years ago. I bought some DC voltmeters from China. They display 3 digits. They read from 0 to 99.9 volts. I coulg
get 4 of them for less than $ 15 including the shipping. I hooked all 4
of them in parallel with a Fluke 87 . Three of them tracked right along
with the Fluke with the last digit sometimes being one high or low from
0 to 24 volts. The fourth one was off by an average of 2 on the last
digit. I found an adjustment screw on the back of the meter and tweaked
it and re ran the test. It then fell in line with the other meters.
I had 3 or 4 of the Harbor Freight 'free' multimeters. The ones that
usually sell for around $ 5. They seem to be reasonable accurate for
the money. Plenty accurate for the home user to test things around the house. I do admit that the safety issue of putting them across the 120
or 240 volt power wires is somewhat doubtful. I sure would not use one
where I worked to put across the 480 volt 3 phase system that is fused
with 200 amps.
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Wed, 24 Jun 2020 21:06:04 +0100, Rich <rich@example.invalid> wrote:
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Thu, 18 Jun 2020 15:38:46 +0100, Pimpom <nobody@nowhere.com> wrote: >>>>
On 6/18/2020 6:33 PM, Commander Kinsey wrote:
I just bought an amp clamp meter, and it states the error is "+/-
1.9% + 3 digits". What does the "3 digits" part mean?
If your meter should read, say 1.875 A, the correct reading could
be anywhere from 1.872 to 1.878. This is a possible error in the
display presented to you in the analog-digital display conversion
process. The +/-1.9% possible error is about the measurement
taken including - but not only - any error made by the sensor.
Thanks, I wonder why all my other meters only list a % error. Is it
included within it somehow, or are they just lying, or do some meters
not have this error?
One generally finds the percentage plus digits error measures on more
expensive equipment. Less expensive equipment more often than not only
lists a percentage and nothing more.
So should I assume the cheaper ones are lying? Or have they just made a rough estimate adding the two errors?
might be both. I dug out my first DMM, a Wavetek DM2, circa 1990s. It might have been from a raffle or something like that.
The DC voltage specs range from 0.8% +1 digit (not bad really) over to the AC ranges which are "1.2% RDG +10 Digits".
If I had new leads, I'd trust it
with outlet voltage, but would stay away from 208volts.
In sci.electronics.equipment Ralph Mowery <rmowery28146@earthlink.net> wrote:
In article <rdecuc$m73$1@reader1.panix.com>, presence@MUNGEpanix.com
says...
So should I assume the cheaper ones are lying? Or have they just made a rough estimate adding the two errors?
might be both. I dug out my first DMM, a Wavetek DM2, circa 1990s. It might >>> have been from a raffle or something like that.
The DC voltage specs range from 0.8% +1 digit (not bad really) over to the >>> AC ranges which are "1.2% RDG +10 Digits". If I had new leads, I'd trust it >>> with outlet voltage, but would stay away from 208volts. The meter has 3.5 >>> digits or max display of 1999. I'm figuring a real 100volt AC reading could >>> be 99 to 101 plus another error of +/- 1 volt for the 10 digits tolerance >>> on the display or count. so 100volts from your Japanese outlet reference >>> might read 98 to 102 volts. So while in the ballpark, it's better than you >>> can read off a Simpson 260 meter in the AC voltage range. I could be wrong >>> on this too.
It's a pretty decent meter for poking at DC circuits for the tens of
dollars is must have cost when new.
It seems that maybe due to modern manufactoring the meters are more
accurate than they were 20 years ago. I bought some DC voltmeters from
China. They display 3 digits. They read from 0 to 99.9 volts. I coulg
get 4 of them for less than $ 15 including the shipping. I hooked all 4
of them in parallel with a Fluke 87 . Three of them tracked right along
with the Fluke with the last digit sometimes being one high or low from
0 to 24 volts. The fourth one was off by an average of 2 on the last
digit. I found an adjustment screw on the back of the meter and tweaked
it and re ran the test. It then fell in line with the other meters.
Have you run this test with AC? That seems to be where the wheels come
off. I brought up this thread to a friend and he mentioned his quest to repair some sort of HP true RMS meter that uses a thermocouple and heater
to properly measure complex waveforms. I can't even guess how slow such a meter might be.
I had 3 or 4 of the Harbor Freight 'free' multimeters. The ones that
usually sell for around $ 5. They seem to be reasonable accurate for
the money. Plenty accurate for the home user to test things around the
house. I do admit that the safety issue of putting them across the 120
or 240 volt power wires is somewhat doubtful. I sure would not use one
where I worked to put across the 480 volt 3 phase system that is fused
with 200 amps.
I'm pretty timid with anything upstream from a plain outlet.
I had an
edison base fuse burst in my hand once. Never seen one come apart before.
It was just a 120v lighting circuit, but right off the service panel.
There's way more excitement near those things.
On 2/07/2020 10:41 pm, Ralph Mowery wrote:I find it crazy that you can select volts and have the wires in the amps holes. The switch should change the contacts. I've broken a meter doing that, just measuring the voltage on a car battery. u100 meter, but UNFUSED FFS! At least the mA range was fused, but they couldn't be bothered putting in a 20A fuse for the big range....
In article <rdjsa6$28b$1@reader1.panix.com>, presence@MUNGEpanix.comAhh the old "Leaving it on amps" trick. How many of us can say they
says...
Have you run this test with AC? That seems to be where the wheels come
off. I brought up this thread to a friend and he mentioned his quest to
repair some sort of HP true RMS meter that uses a thermocouple and heater >>> to properly measure complex waveforms. I can't even guess how slow such a >>> meter might be.
I had 3 or 4 of the Harbor Freight 'free' multimeters. The ones that
usually sell for around $ 5. They seem to be reasonable accurate for
the money. Plenty accurate for the home user to test things around the >>>> house. I do admit that the safety issue of putting them across the 120 >>>> or 240 volt power wires is somewhat doubtful. I sure would not use one >>>> where I worked to put across the 480 volt 3 phase system that is fused >>>> with 200 amps.
I'm pretty timid with anything upstream from a plain outlet. I had an
edison base fuse burst in my hand once. Never seen one come apart before. >>> It was just a 120v lighting circuit, but right off the service panel.
There's way more excitement near those things.
I have not ran any tests for AC . The things I work with don't care
about very much about being accurate to more than around 5 %. Usually
it is more of do I have a voltage/current or not.
When I work on most anything other than low voltage (below 100 volts) I
ues either my Simpson 260 analog meter or a Fluke meter that is rated
for cat 3 and 4. If you have not heard of the Cat numbers, they are for
devices used in different power circuits. I don't know the numbers off
hand, but it goes something like this, Cat 1 is for low voltage items,
Cat 2 for things like stoves and refrigerators, Cat 3 for homw
wiring,and Cat 4 for the very high power circuits like I often worked on
like the 480 volt AC and 300 amps.
For a real scare you should see some of the safety movies that Fluke put
out. They show under test conditions what can hapen to inexpensive
meters and their meters under different conditions like having the
meter set for amps and putting across a 480 volt circuit that has plenty
of amps .
never did it ?
In article <rdjsa6$28b$1@reader1.panix.com>, presence@MUNGEpanix.com
says...
Have you run this test with AC? That seems to be where the wheels come
off. I brought up this thread to a friend and he mentioned his quest to
repair some sort of HP true RMS meter that uses a thermocouple and heater
to properly measure complex waveforms. I can't even guess how slow such a
meter might be.
I had 3 or 4 of the Harbor Freight 'free' multimeters. The ones that
usually sell for around $ 5. They seem to be reasonable accurate for
the money. Plenty accurate for the home user to test things around the
house. I do admit that the safety issue of putting them across the 120
or 240 volt power wires is somewhat doubtful. I sure would not use one
where I worked to put across the 480 volt 3 phase system that is fused
with 200 amps.
I'm pretty timid with anything upstream from a plain outlet. I had an
edison base fuse burst in my hand once. Never seen one come apart before.
It was just a 120v lighting circuit, but right off the service panel.
There's way more excitement near those things.
I have not ran any tests for AC . The things I work with don't care
about very much about being accurate to more than around 5 %. Usually
it is more of do I have a voltage/current or not.
When I work on most anything other than low voltage (below 100 volts) I
ues either my Simpson 260 analog meter or a Fluke meter that is rated
for cat 3 and 4. If you have not heard of the Cat numbers, they are for devices used in different power circuits.
I don't know the numbers off
hand, but it goes something like this, Cat 1 is for low voltage items,
Cat 2 for things like stoves and refrigerators, Cat 3 for homw
wiring,and Cat 4 for the very high power circuits like I often worked on
like the 480 volt AC and 300 amps.
For a real scare you should see some of the safety movies that Fluke put
out. They show under test conditions what can hapen to inexpensive
meters and their meters under different conditions like having the
meter set for amps and putting across a 480 volt circuit that has plenty
of amps .
I had 3 or 4 of the Harbor Freight 'free' multimeters. The ones that
usually sell for around $ 5. They seem to be reasonable accurate for
the money. Plenty accurate for the home user to test things around the house. I do admit that the safety issue of putting them across the 120
or 240 volt power wires is somewhat doubtful. I sure would not use one where I worked to put across the 480 volt 3 phase system that is fused with 200 amps.
Whyever not? Even the cheap ones usually state you can use them up to 1000 volts. I've used them on 240 and 415 just fine. I used one on 2000 volts once, and it just failed inside, not even smoke or noise.
Safety movies designed to sell Fluke meters, and you fell for them hook line and sinker.
In article <op.0nu3kdf9wdg98l@glass>, CFKinsey@military.org.jp says...
Safety movies designed to sell Fluke meters, and you fell for them hook line and sinker.
No, I have actually seen a few blowups and the results of some others.
Have you ever worked at a place that has lots of 480 volt 3 phase
equipment ?
I did before retiring. One learns to respect what can hapen.
He is just an arc flash away from making an ash of himself.
208 is a standard three phase voltage. It is three 120 volt lines phased 120 degrees apart.
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Sun, 12 Jul 2020 20:21:10 +0100, Tom Gardner <spamjunk@blueyonder.co.uk> wrote:
On 12/07/20 19:01, Pimpom wrote:
On 7/12/2020 11:15 PM, Commander Kinsey wrote:
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com>.....<snip>........
wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
My mechanical slide caliper has a resolution of 0.001 inch. This >>>>>>> means that it can display measurements with a precision of 1 mil, >>>>>>What if your caliper had a resolution of 1 mil +/- 3 counts on the last >>>>>> digit?
In America, what is a "mill"? In the UK, it used to mean a thousandth of an
inch, but people use it to mean a millimetre nowadays.
It's not a mill. It's mil - single l. It means, and has always meant, a >>>> thousandth of an inch. It's not an Americanism.
In the UK "mill" means millilitre.
If you want to refer to fractions of an inch, then
it is /always/ "thou", i.e. thousandths of an inch.
In the UK "mil/mill" /never/ means 0.001".
Yes it does. My neighbour's a tradesman (in Scotland) and says
"mill/mil" (I don't know which as they sound the same in speech) as
shorthand for millimetre. As in "that kitchen unit is 600 mill wide".
Since we don't use inches for such things in the UK, there's no
confusion.
The context there is key too. While I'd not measure a countertop or
whatever in millimeters, it would make no sense that anything in a kitchen would be measured thicknesses of paper.
We (in the US) use "guage" for wire
and sheet metal.
We also use "guage"
for measuring really thin stuff like plastic films. In the last case, it's
a completly different unit, but with proper context won't confuse anybody.
Question for the metric woodworkers. Does anybody cut a piece of wood to 317mm or 429mm or other off numbers when building a house or handing a
door or installing a countertop?
He is just an arc flash away from making an ash of himself.
I've done that actually, just scorched my hand for a couple of weeks.
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Sun, 12 Jul 2020 20:21:10 +0100, Tom Gardner <spamjunk@blueyonder.co.uk> wrote:
On 12/07/20 19:01, Pimpom wrote:
On 7/12/2020 11:15 PM, Commander Kinsey wrote:
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com>.....<snip>........
wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
My mechanical slide caliper has a resolution of 0.001 inch. This >>>>>>> means that it can display measurements with a precision of 1 mil, >>>>>>What if your caliper had a resolution of 1 mil +/- 3 counts on the last >>>>>> digit?
In America, what is a "mill"? In the UK, it used to mean a thousandth of an
inch, but people use it to mean a millimetre nowadays.
It's not a mill. It's mil - single l. It means, and has always meant, a >>>> thousandth of an inch. It's not an Americanism.
In the UK "mill" means millilitre.
If you want to refer to fractions of an inch, then
it is /always/ "thou", i.e. thousandths of an inch.
In the UK "mil/mill" /never/ means 0.001".
Yes it does. My neighbour's a tradesman (in Scotland) and says
"mill/mil" (I don't know which as they sound the same in speech) as
shorthand for millimetre. As in "that kitchen unit is 600 mill wide".
Since we don't use inches for such things in the UK, there's no
confusion.
The context there is key too. While I'd not measure a countertop or
whatever in millimeters, it would make no sense that anything in a kitchen would be measured thicknesses of paper.
We (in the US) use "guage" for wire and sheet metal. We also use "guage"
for measuring really thin stuff like plastic films. In the last case, it's
a completly different unit, but with proper context won't confuse anybody.
Question for the metric woodworkers. Does anybody cut a piece of wood to 317mm or 429mm or other off numbers when building a house or handing a
door or installing a countertop?
On Fri, 03 Jul 2020 02:20:53 +0100, RheillyPhoull <Rheilly@bigslong.com> wrote:
On 2/07/2020 10:41 pm, Ralph Mowery wrote:
For a real scare you should see some of the safety movies thatAhh the old "Leaving it on amps" trick. How many of us can say they
Fluke put out. They show under test conditions what can hapen to
inexpensive meters and their meters under different conditions like
having the meter set for amps and putting across a 480 volt circuit
that has plenty of amps .
never did it ?
I find it crazy that you can select volts and have the wires in the
amps holes. The switch should change the contacts. I've broken a
meter doing that, just measuring the voltage on a car battery. u100
meter, but UNFUSED FFS! At least the mA range was fused, but they
couldn't be bothered putting in a 20A fuse for the big range....
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:Then you put the amps ranges on one end of the dial. You would never go through them. And what idiot turns the dial while it's connected?!
On Fri, 03 Jul 2020 02:20:53 +0100, RheillyPhoull <Rheilly@bigslong.com> wrote:
On 2/07/2020 10:41 pm, Ralph Mowery wrote:
For a real scare you should see some of the safety movies thatAhh the old "Leaving it on amps" trick. How many of us can say they>>> never did it ?
Fluke put out. They show under test conditions what can hapen to
inexpensive meters and their meters under different conditions like>>>> having the meter set for amps and putting across a 480 volt circuit>>>> that has plenty of amps .
I find it crazy that you can select volts and have the wires in the
amps holes. The switch should change the contacts. I've broken a
meter doing that, just measuring the voltage on a car battery. u100
meter, but UNFUSED FFS! At least the mA range was fused, but they
couldn't be bothered putting in a 20A fuse for the big range....
The separate amps jacks exist for at least two reasons:
1) If the range switch also switched in/out the current shunt, then the
user could accidentally create a short circult across the probe tips
simply by turning the range switch to or across the amps measurement
ranges. Even if they were quickly turning /across/ the amps settings
ranges, a brief short circuit would be created, which would cause
damage to the meter as well as the device under test depending upon
what was connected at the time.
2) By having the amps jacks separate, the range switch itself does not> have to have contacts beefy enough to carry the current for the ampsOr a relay.
settings. Remember, when measuring amps, the current being measured
flows *through* the meter itself. This would require very different
(and likely much more expensive) range switch contacts.
Some meters do have sensors for the amps jacks that sound an alarm if--- Synchronet 3.21d-Linux NewsLink 1.2
the probes are inserted in the amps jacks but the range switch is on a> different setting than amperes.
On Fri, 17 Jul 2020 15:02:16 +0100, Rich <rich@example.invalid> wrote:
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Fri, 03 Jul 2020 02:20:53 +0100, RheillyPhoull <Rheilly@bigslong.com> wrote:
On 2/07/2020 10:41 pm, Ralph Mowery wrote:
For a real scare you should see some of the safety movies thatAhh the old "Leaving it on amps" trick. How many of us can say they
Fluke put out. They show under test conditions what can hapen to
inexpensive meters and their meters under different conditions like
having the meter set for amps and putting across a 480 volt circuit
that has plenty of amps .
never did it ?
I find it crazy that you can select volts and have the wires in the
amps holes. The switch should change the contacts. I've broken a
meter doing that, just measuring the voltage on a car battery. u100
meter, but UNFUSED FFS! At least the mA range was fused, but they
couldn't be bothered putting in a 20A fuse for the big range....
The separate amps jacks exist for at least two reasons:
1) If the range switch also switched in/out the current shunt, then the
user could accidentally create a short circult across the probe tips
simply by turning the range switch to or across the amps measurement
ranges. Even if they were quickly turning /across/ the amps settings
ranges, a brief short circuit would be created, which would cause
damage to the meter as well as the device under test depending upon
what was connected at the time.
Then you put the amps ranges on one end of the dial. You would never
go through them.
And what idiot turns the dial while it's connected?!
2) By having the amps jacks separate, the range switch itself does not
have to have contacts beefy enough to carry the current for the amps
settings. Remember, when measuring amps, the current being measured
flows *through* the meter itself. This would require very different
(and likely much more expensive) range switch contacts.
Or a relay.
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:Then don't make them like that.
On Fri, 17 Jul 2020 15:02:16 +0100, Rich <rich@example.invalid> wrote:
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Fri, 03 Jul 2020 02:20:53 +0100, RheillyPhoull <Rheilly@bigslong.com> wrote:
On 2/07/2020 10:41 pm, Ralph Mowery wrote:
For a real scare you should see some of the safety movies thatAhh the old "Leaving it on amps" trick. How many of us can say they >>>>> never did it ?
Fluke put out. They show under test conditions what can hapen to>>>>>> inexpensive meters and their meters under different conditions like
having the meter set for amps and putting across a 480 volt circuit >>>>>> that has plenty of amps .
I find it crazy that you can select volts and have the wires in the>>>> amps holes. The switch should change the contacts. I've broken a
meter doing that, just measuring the voltage on a car battery. u100
meter, but UNFUSED FFS! At least the mA range was fused, but they
couldn't be bothered putting in a 20A fuse for the big range....
The separate amps jacks exist for at least two reasons:
1) If the range switch also switched in/out the current shunt, then the
user could accidentally create a short circult across the probe tips>>> simply by turning the range switch to or across the amps measurement>>> ranges. Even if they were quickly turning /across/ the amps settings
ranges, a brief short circuit would be created, which would cause
damage to the meter as well as the device under test depending upon
what was connected at the time.
Then you put the amps ranges on one end of the dial. You would never>> go through them.
Some meters have range switches that rotate through a full 360 degrees> with no stops - there would be no "end of the dial" in those instances.
And even with an 'end of the dial' there is still the possibility ofThen have a gap which is connected to nothing.
landing 'off by one' while turning the dial.
Wrong. You adjust the dial to what you want to do, not remembering what you were measuring yesterday. Having only one thing to change makes it way easier to get it right.And what idiot turns the dial while it's connected?!
The same idiot who'd leave the leads plugged into the amps jacks and
then attempt to measure the voltage of a car battery
(or some other low impedance high current voltage source).It only has to get over 20 amps to fuck the meter.
I suspect you would find changing the range switch while connected isMeters should always auto range. Mine all do, and I've never even considered adjusting the dial while it's connected. I'm not going to change between resistance, current, and volts and want to leave it connected to the same thing.
much more common than your response implies. Esp. for switching
up/down a range for meters that are not auto-ranging.
No, because you save on an extra socket.2) By having the amps jacks separate, the range switch itself does not
have to have contacts beefy enough to carry the current for the amps>>> settings. Remember, when measuring amps, the current being measured>>> flows *through* the meter itself. This would require very different>>> (and likely much more expensive) range switch contacts.
Or a relay.
Which also equates directly to added expense vs. having the user
themselves be that "relay".
And for battery powered meters, shorterLatching relays use very little indeed, like the one in my room thermostat. 2 AA batteries last years.
battery life (due to the current consumed by the relay coil).
It is also possible (this is a guess in my part) that the CAT ratingsThen they're fools, because now "user can obtain short circuit by forgetting he was measuring current yesterday, or because a colleague was without him knowing". If it was selected on the dial, there is no possibility to make a mistake. You select what you want and that's what you get. It's illogical to have one thing pointing at volts while another thing is expecting current!
specify separate amps jacks for an added safety factor of "user must deliberately move lead to obtain short circuit through meter".
As well, the user who'd leave the leads plugged into amps, and then tryNope. I pick up a multimeter and set it to what I'm about to measure. Same way as I don't drive into my house because I left my car in forward gear yesterday.
to measure voltage on car battery or other high current source is also> just as likely to leave the range switch in the amps setting (after
having measured current somewhere) and subsequently try to measure
voltage.
It is not possible to fully protect users who don't payPeople make mistakes. The best equipment prevents this. My VW Golf for example would not allow me to select 1st gear when going 100mph. It was quite clever in fact. I could do that on purpose and it would drop one gear at a time to slow the car as quickly as possible to assist the brakes in an emergency. And yes I did try it a few times, one time I scared the shit out of the passenger (who had never seen an automatic gearbox before).
attention from doing stupid things. Either they forget to unplug from> the amps jack, or they forget to switch away from the amps range,
either way they get a local fireworks display of their own doing.
I suspect you would find changing the range switch while connected is
much more common than your response implies. Esp. for switching
up/down a range for meters that are not auto-ranging.
2) By having the amps jacks separate, the range switch itself does not
have to have contacts beefy enough to carry the current for the amps
settings. Remember, when measuring amps, the current being measured
flows *through* the meter itself. This would require very different
(and likely much more expensive) range switch contacts.
Or a relay.
Which also equates directly to added expense vs. having the user
themselves be that "relay". And for battery powered meters, shorter
battery life (due to the current consumed by the relay coil).
It is also possible (this is a guess in my part) that the CAT ratings specify separate amps jacks for an added safety factor of "user must deliberately move lead to obtain short circuit through meter".
As well, the user who'd leave the leads plugged into amps, and then try
to measure voltage on car battery or other high current source is also
just as likely to leave the range switch in the amps setting (after
having measured current somewhere) and subsequently try to measure
voltage. It is not possible to fully protect users who don't pay
attention from doing stupid things. Either they forget to unplug from
the amps jack, or they forget to switch away from the amps range,
either way they get a local fireworks display of their own doing.
In article <ret1h6$stk$1@dont-email.me>, rich@example.invalid says...
I suspect you would find changing the range switch while connected is
much more common than your response implies. Esp. for switching
up/down a range for meters that are not auto-ranging.
2) By having the amps jacks separate, the range switch itself does not
have to have contacts beefy enough to carry the current for the amps
settings. Remember, when measuring amps, the current being measured
flows *through* the meter itself. This would require very different
(and likely much more expensive) range switch contacts.
Or a relay.
Which also equates directly to added expense vs. having the user
themselves be that "relay". And for battery powered meters, shorter
battery life (due to the current consumed by the relay coil).
It is also possible (this is a guess in my part) that the CAT ratings
specify separate amps jacks for an added safety factor of "user must
deliberately move lead to obtain short circuit through meter".
As well, the user who'd leave the leads plugged into amps, and then try
to measure voltage on car battery or other high current source is also
just as likely to leave the range switch in the amps setting (after
having measured current somewhere) and subsequently try to measure
voltage. It is not possible to fully protect users who don't pay
attention from doing stupid things. Either they forget to unplug from
the amps jack, or they forget to switch away from the amps range,
either way they get a local fireworks display of their own doing.
I often leave the leads connected to a Simpson 260 and change voltage
ranges. Where I worked there were so many wires in a conduit carrring
120 VAC control voltage it was difficult to tell if the voltage was
'real' or induced by the coupling. I found out that if I started on the
500 volt range and then switched to the 250 volt range if the meter
pointer stayed in the same relative position I could then switch to the
50 volt range and the meter pointer would still be near the same
relative position if the voltage was induced. If the pointer changed positions to follow the 120 VAC when going to the 250 volt scale the
voltage was real.
I doubt that the CAT rating requies seperate Amps positions for the
leads. Fluke uses special fuses in their meters to get the CAT ratings.
They do not have a seperate jack for the ohms settings either which is
more likely where the meter would be set. Most of the time the
circuit would have to be broken and the meter inserted to measuer amps.
As you say it is impossiable to fully protect everyone from doing
somethen forgetful or stupid, but having a $ 300 meter instead of a $ 5 dollar one goes a long ways.
I do have a Fluke test meter that is purty much fool proof up to 600
volts and rated CAT 4. A T1000. It only measuers AC amps by passing a
wire through the prongs. It does have a switch for voltage and ohms. I
have on purpose set it to ohms and put it across a fuse in a 480 volt AC circuit to see if the fuse is good or bad. No problem to do this.
On Fri, 17 Jul 2020 21:26:15 +0100, Rich <rich@example.invalid> wrote:
As well, the user who'd leave the leads plugged into amps, and then
try to measure voltage on car battery or other high current source
is also just as likely to leave the range switch in the amps setting
(after having measured current somewhere) and subsequently try to
measure voltage.
Nope. I pick up a multimeter and set it to what I'm about to
measure. Same way as I don't drive into my house because I left my
car in forward gear yesterday.
I do have a Fluke test meter that is purty much fool proof up to 600
volts and rated CAT 4. A T1000. It only measuers AC amps by passing a
wire through the prongs. It does have a switch for voltage and ohms. I have on purpose set it to ohms and put it across a fuse in a 480 volt AC circuit to see if the fuse is good or bad. No problem to do this.
With a bad fuse it doesn't blow up?
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:No, because it's illogical to change two things to set one thing.
On Fri, 17 Jul 2020 21:26:15 +0100, Rich <rich@example.invalid> wrote:
As well, the user who'd leave the leads plugged into amps, and then
try to measure voltage on car battery or other high current source
is also just as likely to leave the range switch in the amps setting>>> (after having measured current somewhere) and subsequently try to
measure voltage.
Nope. I pick up a multimeter and set it to what I'm about to
measure. Same way as I don't drive into my house because I left my
car in forward gear yesterday.
Interesting....
Yet you said this yesterday:
From: "Commander Kinsey" <CFKinsey@military.org.jp>
Date: Thu, 16 Jul 2020 20:09:20 +0100
Message-ID: <op.0nu3hup8wdg98l@glass>
...
I find it crazy that you can select volts and have the wires in the
amps holes. ... I've broken a meter doing that, just measuring the
voltage on a car battery. A u100 meter, but UNFUSED FFS!
...
One aspect of "set it to what I'm about to measure" should normally
include: "are the leads in the correct jacks".
In article <op.0nw7h4ytwdg98l@glass>, CFKinsey@military.org.jp says...
I do have a Fluke test meter that is purty much fool proof up to 600
volts and rated CAT 4. A T1000. It only measuers AC amps by passing a
wire through the prongs. It does have a switch for voltage and ohms. I >> > have on purpose set it to ohms and put it across a fuse in a 480 volt AC >> > circuit to see if the fuse is good or bad. No problem to do this.
With a bad fuse it doesn't blow up?
No it does not . It is designed to protect its self from voltage on the
ohms scale. They are only about $ 130
Even better is a quick tester by Fluke. it has 2 leads and about 8 or
so leds on it. Both it and the T1000 look similar to bannanas, even
yellow in color. The 2nd tester is fully automatic. Connect the two
leads to anything under 600 or so volts. If voltage, the leds light up
, the more for more voltage. Anoter is for AC or DC. If there is less
than about 200 ohms and no voltage, there is a led and buzzer for that.
About as fool proof as they make it for quick tests.
I do have a Fluke test meter that is purty much fool proof up to 600
volts and rated CAT 4. A T1000. It only measuers AC amps by passing a
wire through the prongs. It does have a switch for voltage and ohms. I have on purpose set it to ohms and put it across a fuse in a 480 volt AC circuit to see if the fuse is good or bad. No problem to do this.
With a bad fuse it doesn't blow up?
About as fool proof as they make it for quick tests.
Does it check for current if there's no voltage?
On 13/07/20 16:39, Jeroen Belleman wrote:
On 2020-07-13 17:27, Pimpom wrote:
On 7/13/2020 6:06 PM, Commander Kinsey wrote:[...]
If you're not American why did you say "my bad"? Your bad what? Finish theSo now you're a grammar Nazi? This after I (and others) spent considerable >>> time and effort[...]
sentence!
Just drop it. There are better things to do than to argue
with a cantankerous teenager. If a conversation turns into
a source of irritation, the best way is to simply drop out.
Precisely.
That was my decision too. An easy decision given the moniker
"Commander Kinsey" is either someone that has too high a
regard for themselves, or is indicating that they intend to
troll.
On 7/13/2020 6:06 PM, Commander Kinsey wrote:
On Mon, 13 Jul 2020 05:53:29 +0100, Pimpom <nobody@nowhere.com> wrote:So now you're a grammar Nazi? This after I (and others) spent
On 7/13/2020 12:51 AM, Tom Gardner wrote:
On 12/07/20 19:01, Pimpom wrote:
On 7/12/2020 11:15 PM, Commander Kinsey wrote:
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com>.....<snip>........
wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
My mechanical slide caliper has a resolution of 0.001 inch. This >>>>>>>> means that it can display measurements with a precision of 1 mil, >>>>>>>What if your caliper had a resolution of 1 mil +/- 3 counts on the last >>>>>>> digit?
In America, what is a "mill"? In the UK, it used to mean a thousandth of an
inch, but people use it to mean a millimetre nowadays.
It's not a mill. It's mil - single l. It means, and has always meant, a >>>>> thousandth of an inch. It's not an Americanism.
In the UK "mill" means millilitre.
If you want to refer to fractions of an inch, then
it is /always/ "thou", i.e. thousandths of an inch.
In the UK "mil/mill" /never/ means 0.001".
My bad. This is the first time I heard that the mil is not used
as the unit for .001" in the UK. (I'm *not* an American).
If you're not American why did you say "my bad"? Your bad what? Finish the sentence!
considerable time and effort patiently explaining to you a
concept that many/most readers here probably already knew, and
would quickly grasp if they didn't. Sheesh!
And is there a law against non-Americans using an American
expression? FYI I'm none of these: American, British, Australian
or Canadian - or a citizen of any other country where English is
natively spoken.
On Thu, 16 Jul 2020 08:30:20 +0100, Cydrome Leader <presence@mungepanix.com> wrote:
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Sun, 12 Jul 2020 20:21:10 +0100, Tom Gardner <spamjunk@blueyonder.co.uk> wrote:
On 12/07/20 19:01, Pimpom wrote:
On 7/12/2020 11:15 PM, Commander Kinsey wrote:
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com>.....<snip>........
wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
My mechanical slide caliper has a resolution of 0.001 inch. This >>>>>>>> means that it can display measurements with a precision of 1 mil, >>>>>>>What if your caliper had a resolution of 1 mil +/- 3 counts on the last >>>>>>> digit?
In America, what is a "mill"? In the UK, it used to mean a thousandth of an
inch, but people use it to mean a millimetre nowadays.
It's not a mill. It's mil - single l. It means, and has always meant, a >>>>> thousandth of an inch. It's not an Americanism.
In the UK "mill" means millilitre.
If you want to refer to fractions of an inch, then
it is /always/ "thou", i.e. thousandths of an inch.
In the UK "mil/mill" /never/ means 0.001".
Yes it does. My neighbour's a tradesman (in Scotland) and says
"mill/mil" (I don't know which as they sound the same in speech) as
shorthand for millimetre. As in "that kitchen unit is 600 mill wide".
Since we don't use inches for such things in the UK, there's no
confusion.
The context there is key too. While I'd not measure a countertop or
whatever in millimeters, it would make no sense that anything in a kitchen >> would be measured thicknesses of paper.
We (in the US) use "guage" for wire
Isn't that really hard to work out? We use cross sectional area in mm. Which is really easy to imagine. With the added bonus that a higher number is thicker. It's also pretty handy as a rough guide that 1 square mm carries 10 amps.
and sheet metal.
Seriously? Wow. Why would you nbot measure a thickness in a unit of distance?
We also use "guage"
for measuring really thin stuff like plastic films. In the last case, it's >> a completly different unit, but with proper context won't confuse anybody.
We use microns.
Question for the metric woodworkers. Does anybody cut a piece of wood to
317mm or 429mm or other off numbers when building a house or handing a
door or installing a countertop?
Depends if something else is in the way. I'd always try to use round numbers.
On Mon, 13 Jul 2020 16:27:26 +0100, Pimpom <nobody@nowhere.com> wrote:
On 7/13/2020 6:06 PM, Commander Kinsey wrote:
On Mon, 13 Jul 2020 05:53:29 +0100, Pimpom <nobody@nowhere.com> wrote:So now you're a grammar Nazi? This after I (and others) spent
My bad. This is the first time I heard that the mil is not used
as the unit for .001" in the UK. (I'm *not* an American).
If you're not American why did you say "my bad"? Your bad what? Finish the sentence!
considerable time and effort patiently explaining to you a
concept that many/most readers here probably already knew, and
would quickly grasp if they didn't. Sheesh!
And is there a law against non-Americans using an American
expression? FYI I'm none of these: American, British, Australian
or Canadian - or a citizen of any other country where English is
natively spoken.
It's not grammar, it's missing off an entuire word, the one with the meaning in it!
It's like saying "Today I went out and did some".
In article <ret1h6$stk$1@dont-email.me>, rich@example.invalid says...
I suspect you would find changing the range switch while connected is
much more common than your response implies. Esp. for switching
up/down a range for meters that are not auto-ranging.
2) By having the amps jacks separate, the range switch itself does not
have to have contacts beefy enough to carry the current for the amps
settings. Remember, when measuring amps, the current being measured
flows *through* the meter itself. This would require very different
(and likely much more expensive) range switch contacts.
Or a relay.
Which also equates directly to added expense vs. having the user
themselves be that "relay". And for battery powered meters, shorter
battery life (due to the current consumed by the relay coil).
It is also possible (this is a guess in my part) that the CAT ratings
specify separate amps jacks for an added safety factor of "user must
deliberately move lead to obtain short circuit through meter".
As well, the user who'd leave the leads plugged into amps, and then try
to measure voltage on car battery or other high current source is also
just as likely to leave the range switch in the amps setting (after
having measured current somewhere) and subsequently try to measure
voltage. It is not possible to fully protect users who don't pay
attention from doing stupid things. Either they forget to unplug from
the amps jack, or they forget to switch away from the amps range,
either way they get a local fireworks display of their own doing.
I often leave the leads connected to a Simpson 260 and change voltage ranges. Where I worked there were so many wires in a conduit carrring
120 VAC control voltage it was difficult to tell if the voltage was
'real' or induced by the coupling. I found out that if I started on the
500 volt range and then switched to the 250 volt range if the meter
pointer stayed in the same relative position I could then switch to the
50 volt range and the meter pointer would still be near the same
relative position if the voltage was induced. If the pointer changed positions to follow the 120 VAC when going to the 250 volt scale the
voltage was real.
I doubt that the CAT rating requies seperate Amps positions for the
leads. Fluke uses special fuses in their meters to get the CAT ratings. They do not have a seperate jack for the ohms settings either which is
more likely where the meter would be set. Most of the time the
circuit would have to be broken and the meter inserted to measuer amps.
As you say it is impossiable to fully protect everyone from doing
somethen forgetful or stupid, but having a $ 300 meter instead of a $ 5 dollar one goes a long ways.
I do have a Fluke test meter that is purty much fool proof up to 600
volts and rated CAT 4. A T1000. It only measuers AC amps by passing a
wire through the prongs. It does have a switch for voltage and ohms. I have on purpose set it to ohms and put it across a fuse in a 480 volt AC circuit to see if the fuse is good or bad. No problem to do this.
In article <op.0nw7h4ytwdg98l@glass>, CFKinsey@military.org.jp says...
I do have a Fluke test meter that is purty much fool proof up to 600
volts and rated CAT 4. A T1000. It only measuers AC amps by passing a
wire through the prongs. It does have a switch for voltage and ohms. I >> > have on purpose set it to ohms and put it across a fuse in a 480 volt AC >> > circuit to see if the fuse is good or bad. No problem to do this.
With a bad fuse it doesn't blow up?
No it does not . It is designed to protect its self from voltage on the ohms scale. They are only about $ 130
Even better is a quick tester by Fluke. it has 2 leads and about 8 or
so leds on it. Both it and the T1000 look similar to bannanas, even
yellow in color. The 2nd tester is fully automatic. Connect the two
leads to anything under 600 or so volts. If voltage, the leds light up
, the more for more voltage. Anoter is for AC or DC. If there is less
than about 200 ohms and no voltage, there is a led and buzzer for that.
About as fool proof as they make it for quick tests.
I do have a Fluke test meter that is purty much fool proof up to 600
volts and rated CAT 4. A T1000. It only measuers AC amps by passing a wire through the prongs. It does have a switch for voltage and ohms. I have on purpose set it to ohms and put it across a fuse in a 480 volt AC circuit to see if the fuse is good or bad. No problem to do this.
I just got one of those clamp current multimeters. I noticed some glaring limitations vs the full out Fluke 87 V, but at the same time, it's way
more "idiot-proof".
The current ranges, even for DC at only available though the current
clamp. It's just not possible to short anything out with the test probes. The downside (not really surprising) is no low current ranges. Ok fine.
The input impedance is pretty low at 1Meg as well, but for poking at line voltage wiring, this is fine. Again, no matter what range you are set it,
it appears to be impossible to blow up the meter as it has no low
resistance across the leads modes. The ohms range seems to max out at 40k
or something surprisibly low like that, again, no big deal for prodding at lighting circuits or an outlet, or some 24 volt circuit.
Hmm, Remeber those neon voltage testers with two leads and the bizarre
shirt pocket clip? I had one go out on me, showed no voltage when there
was some. Whoops.
Now I use one of those ground/wiring testers. I figure it will still light up if one neon indicator fails.
In article <op.0nvd9pimwdg98l@glass>, CFKinsey@military.org.jp says...
He is just an arc flash away from making an ash of himself.
I've done that actually, just scorched my hand for a couple of weeks.
If you had respected things that probably would never hapen, you would
not have scorched your hand.
On Fri, 17 Jul 2020 04:29:38 +0100, Ralph Mowery <rmowery28146@earthlink.net> wrote:
In article <op.0nvd9pimwdg98l@glass>, CFKinsey@military.org.jp says...
He is just an arc flash away from making an ash of himself.
I've done that actually, just scorched my hand for a couple of weeks.
If you had respected things that probably would never hapen, you would
not have scorched your hand.
You miss the point, it's not the end of the world.
Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Fri, 17 Jul 2020 04:29:38 +0100, Ralph Mowery <rmowery28146@earthlink.net> wrote:
In article <op.0nvd9pimwdg98l@glass>, CFKinsey@military.org.jp says...
He is just an arc flash away from making an ash of himself.
I've done that actually, just scorched my hand for a couple of weeks.
If you had respected things that probably would never hapen, you would
not have scorched your hand.
You miss the point, it's not the end of the world.
A scorched hand, no, not the end of the world.
A stopped heart, which *can* happen if the arc flash conducts enough
current through the wrong part of the body, well then for the one who's
heart just got stopped it might just be the end of the world.
On Thu, 02 Jul 2020 06:45:42 +0100, Cydrome Leader <presence@mungepanix.com> wrote:
In sci.electronics.equipment Ralph Mowery <rmowery28146@earthlink.net> wrote:
In article <rdecuc$m73$1@reader1.panix.com>, presence@MUNGEpanix.com
says...
So should I assume the cheaper ones are lying? Or have they just made a rough estimate adding the two errors?
might be both. I dug out my first DMM, a Wavetek DM2, circa 1990s. It might
have been from a raffle or something like that.
The DC voltage specs range from 0.8% +1 digit (not bad really) over to the
AC ranges which are "1.2% RDG +10 Digits". If I had new leads, I'd trust it
with outlet voltage, but would stay away from 208volts. The meter has 3.5 >>>> digits or max display of 1999. I'm figuring a real 100volt AC reading could
be 99 to 101 plus another error of +/- 1 volt for the 10 digits tolerance >>>> on the display or count. so 100volts from your Japanese outlet reference >>>> might read 98 to 102 volts. So while in the ballpark, it's better than you >>>> can read off a Simpson 260 meter in the AC voltage range. I could be wrong >>>> on this too.
It's a pretty decent meter for poking at DC circuits for the tens of
dollars is must have cost when new.
It seems that maybe due to modern manufactoring the meters are more
accurate than they were 20 years ago. I bought some DC voltmeters from
China. They display 3 digits. They read from 0 to 99.9 volts. I coulg >>> get 4 of them for less than $ 15 including the shipping. I hooked all 4 >>> of them in parallel with a Fluke 87 . Three of them tracked right along >>> with the Fluke with the last digit sometimes being one high or low from
0 to 24 volts. The fourth one was off by an average of 2 on the last
digit. I found an adjustment screw on the back of the meter and tweaked >>> it and re ran the test. It then fell in line with the other meters.
Have you run this test with AC? That seems to be where the wheels come
off. I brought up this thread to a friend and he mentioned his quest to
repair some sort of HP true RMS meter that uses a thermocouple and heater
to properly measure complex waveforms. I can't even guess how slow such a
meter might be.
How well do these things work measuring dodgy waves like from a cheap UPS or invertor?
I had 3 or 4 of the Harbor Freight 'free' multimeters. The ones that
usually sell for around $ 5. They seem to be reasonable accurate for
the money. Plenty accurate for the home user to test things around the
house. I do admit that the safety issue of putting them across the 120
or 240 volt power wires is somewhat doubtful. I sure would not use one
where I worked to put across the 480 volt 3 phase system that is fused
with 200 amps.
I'm pretty timid with anything upstream from a plain outlet.
I've replaced outlets (240V, not the namby pamby USA stuff) without
turning off the power - other outlets on the same circuit were being
used in the office and I saw no point in interrupting them.
Just keep your fingers off the metal things and don't short stuff together. Wear goggles and gloves if you want to be a girl about it.
I had an
edison base fuse burst in my hand once. Never seen one come apart before.
It was just a 120v lighting circuit, but right off the service panel.
There's way more excitement near those things.
Try shorting two phases together with 500A cables. That causes lots of smoke, a fire alarm, 3 fire engines, and a visit from the power company.
Do not ever employ Irish electricians.
On Tue, 30 Jun 2020 04:52:44 +0100, Cydrome Leader <presence@mungepanix.com> wrote:
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Wed, 24 Jun 2020 21:06:04 +0100, Rich <rich@example.invalid> wrote:
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Thu, 18 Jun 2020 15:38:46 +0100, Pimpom <nobody@nowhere.com> wrote: >>>>>
On 6/18/2020 6:33 PM, Commander Kinsey wrote:
I just bought an amp clamp meter, and it states the error is "+/- >>>>>>> 1.9% + 3 digits". What does the "3 digits" part mean?
If your meter should read, say 1.875 A, the correct reading could
be anywhere from 1.872 to 1.878. This is a possible error in the
display presented to you in the analog-digital display conversion
process. The +/-1.9% possible error is about the measurement
taken including - but not only - any error made by the sensor.
Thanks, I wonder why all my other meters only list a % error. Is it >>>>> included within it somehow, or are they just lying, or do some meters >>>>> not have this error?
One generally finds the percentage plus digits error measures on more
expensive equipment. Less expensive equipment more often than not only >>>> lists a percentage and nothing more.
So should I assume the cheaper ones are lying? Or have they just made a rough estimate adding the two errors?
might be both. I dug out my first DMM, a Wavetek DM2, circa 1990s. It might >> have been from a raffle or something like that.
The DC voltage specs range from 0.8% +1 digit (not bad really) over to the >> AC ranges which are "1.2% RDG +10 Digits".
TEN!? Surely that's more than the number of digits it has? In which case it has no accuracy at all.
If I had new leads, I'd trust it
with outlet voltage, but would stay away from 208volts.
You oughta complain about that low voltage. Some equipment needs at
least 220.
On 2020-07-16, Cydrome Leader <presence@MUNGEpanix.com> wrote:
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Sun, 12 Jul 2020 20:21:10 +0100, Tom Gardner <spamjunk@blueyonder.co.uk> wrote:
On 12/07/20 19:01, Pimpom wrote:
On 7/12/2020 11:15 PM, Commander Kinsey wrote:
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com>.....<snip>........
wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
My mechanical slide caliper has a resolution of 0.001 inch. This >>>>>>>> means that it can display measurements with a precision of 1 mil, >>>>>>>What if your caliper had a resolution of 1 mil +/- 3 counts on the last >>>>>>> digit?
In America, what is a "mill"? In the UK, it used to mean a thousandth of an
inch, but people use it to mean a millimetre nowadays.
It's not a mill. It's mil - single l. It means, and has always meant, a >>>>> thousandth of an inch. It's not an Americanism.
In the UK "mill" means millilitre.
If you want to refer to fractions of an inch, then
it is /always/ "thou", i.e. thousandths of an inch.
In the UK "mil/mill" /never/ means 0.001".
Yes it does. My neighbour's a tradesman (in Scotland) and says
"mill/mil" (I don't know which as they sound the same in speech) as
shorthand for millimetre. As in "that kitchen unit is 600 mill wide".
Since we don't use inches for such things in the UK, there's no
confusion.
The context there is key too. While I'd not measure a countertop or
whatever in millimeters, it would make no sense that anything in a kitchen >> would be measured thicknesses of paper.
We (in the US) use "guage" for wire and sheet metal. We also use "guage"
for measuring really thin stuff like plastic films. In the last case, it's >> a completly different unit, but with proper context won't confuse anybody.
sheet metal in mm (1.6mm, 0.65mm etc...)
plastic sheet in microns 40um etc.
electric wire in square mm.
fencing wire in mm diameter.
Question for the metric woodworkers. Does anybody cut a piece of wood to
317mm or 429mm or other off numbers when building a house or handing a
door or installing a countertop?
Yes, if that is the right size. buildings are usually specified in
multiples of 100mm. often multiples of 300mm or 1000mm
furniture usually in multiples of 25mm
Factory door sizes are 620mm + multiples of 50mm, but not all openings
are the right size for the factory door.
Timber sizes for dressed finger-jointed framing timber are accurate to withion 0.5mm are are certain preferred multiples of 5mm eg: 70x35 used mainly for non-structual walls. 90x45 used mainly for structural walls.
The stud spacing and top-plate height will typically be some multiple
of 50mm So a lot of the cutting for studs, and blocking is at multiples
of 5mm. that's if you're not using pre-fabricated framing.
Carpenters use millimeteres. they say centimeters
are for tailors, and inches are for cobblers.
In article <op.0nw9prwrwdg98l@glass>, CFKinsey@military.org.jp says...
About as fool proof as they make it for quick tests.
Does it check for current if there's no voltage?
Just how can there be curent if there is no voltage ?
There is no current by the leads, but works like a clamp on meter to
check for AC Current. Does not do DC current.
There can be voltage but no current.
On 7/21/2020 2:06 AM, Commander Kinsey wrote:
On Mon, 13 Jul 2020 16:27:26 +0100, Pimpom <nobody@nowhere.com> wrote:It took you more than a week to think up that comeback?
On 7/13/2020 6:06 PM, Commander Kinsey wrote:
On Mon, 13 Jul 2020 05:53:29 +0100, Pimpom <nobody@nowhere.com> wrote: >>>>So now you're a grammar Nazi? This after I (and others) spent
My bad. This is the first time I heard that the mil is not used
as the unit for .001" in the UK. (I'm *not* an American).
If you're not American why did you say "my bad"? Your bad what? Finish the sentence!
considerable time and effort patiently explaining to you a
concept that many/most readers here probably already knew, and
would quickly grasp if they didn't. Sheesh!
And is there a law against non-Americans using an American
expression? FYI I'm none of these: American, British, Australian
or Canadian - or a citizen of any other country where English is
natively spoken.
It's not grammar, it's missing off an entuire word, the one with the meaning in it!
Anyway, good luck with your self-appointed job of reforming the usage of American slang which, by the way, has pervaded much of the world
outside the US.
And what does "entuire" mean? Blimey! Skitt's Law, you know, old boy.
It's like saying "Today I went out and did some".That would be quite acceptable if the context were known.
On Tue, 21 Jul 2020 07:35:18 +0100, Pimpom <nobody@nowhere.com> wrote:
On 7/21/2020 2:06 AM, Commander Kinsey wrote:
On Mon, 13 Jul 2020 16:27:26 +0100, Pimpom <nobody@nowhere.com> wrote:It took you more than a week to think up that comeback?
On 7/13/2020 6:06 PM, Commander Kinsey wrote:
On Mon, 13 Jul 2020 05:53:29 +0100, Pimpom <nobody@nowhere.com> wrote: >>>>>So now you're a grammar Nazi? This after I (and others) spent
My bad. This is the first time I heard that the mil is not used
as the unit for .001" in the UK. (I'm *not* an American).
If you're not American why did you say "my bad"? Your bad what? Finish the sentence!
considerable time and effort patiently explaining to you a
concept that many/most readers here probably already knew, and
would quickly grasp if they didn't. Sheesh!
And is there a law against non-Americans using an American
expression? FYI I'm none of these: American, British, Australian
or Canadian - or a citizen of any other country where English is
natively spoken.
It's not grammar, it's missing off an entuire word, the one with the meaning in it!
You think all I do is reply in here?
Anyway, good luck with your self-appointed job of reforming the usage of
American slang which, by the way, has pervaded much of the world
outside the US.
It's not said in the UK. We can speak our own language correctly.
And what does "entuire" mean? Blimey! Skitt's Law, you know, old boy.
Learn the difference between a typo and stupidity.
It's like saying "Today I went out and did some".That would be quite acceptable if the context were known.
Why make your conversations like jpeg encoding?
In sci.electronics.basics Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Thu, 16 Jul 2020 08:30:20 +0100, Cydrome Leader <presence@mungepanix.com> wrote:
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Sun, 12 Jul 2020 20:21:10 +0100, Tom Gardner <spamjunk@blueyonder.co.uk> wrote:
On 12/07/20 19:01, Pimpom wrote:
On 7/12/2020 11:15 PM, Commander Kinsey wrote:
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com>.....<snip>........
wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote:
My mechanical slide caliper has a resolution of 0.001 inch. This >>>>>>>>> means that it can display measurements with a precision of 1 mil, >>>>>>>>What if your caliper had a resolution of 1 mil +/- 3 counts on the last
digit?
In America, what is a "mill"? In the UK, it used to mean a thousandth of an
inch, but people use it to mean a millimetre nowadays.
It's not a mill. It's mil - single l. It means, and has always meant, a >>>>>> thousandth of an inch. It's not an Americanism.
In the UK "mill" means millilitre.
If you want to refer to fractions of an inch, then
it is /always/ "thou", i.e. thousandths of an inch.
In the UK "mil/mill" /never/ means 0.001".
Yes it does. My neighbour's a tradesman (in Scotland) and says
"mill/mil" (I don't know which as they sound the same in speech) as
shorthand for millimetre. As in "that kitchen unit is 600 mill wide". >>>> Since we don't use inches for such things in the UK, there's no
confusion.
The context there is key too. While I'd not measure a countertop or
whatever in millimeters, it would make no sense that anything in a kitchen >>> would be measured thicknesses of paper.
We (in the US) use "guage" for wire
Isn't that really hard to work out? We use cross sectional area in mm. Which is really easy to imagine. With the added bonus that a higher number is thicker. It's also pretty handy as a rough guide that 1 square mm carries 10 amps.
Not really. If you can only count with your fingers you probably aren't building anything impressive to start with. The entire fallacy of "metric
is easy, base 10, duh" is just bullshit. Check dimensions of anything designed by people that don't know what fractions are. There are tons of weird numbers like 13.1mm and so forth. It's no different than 1-1/8th inches.
and sheet metal.
Seriously? Wow. Why would you not measure a thickness in a unit of distance?
The guage for sheet metal is sort of obnoxious. It will vary by type of
metal as well, if that makes any sense.
We also use "guage"We use microns.
for measuring really thin stuff like plastic films. In the last case, it's >>> a completly different unit, but with proper context won't confuse anybody. >>
how many microns thick is your plastic trash bag?
The last ones I got were
speced on the box as "0.7 mil" There's no false sense of precision there,
like with the 610mm countertop or whatever it was.
Question for the metric woodworkers. Does anybody cut a piece of wood to >>> 317mm or 429mm or other off numbers when building a house or handing a
door or installing a countertop?
Depends if something else is in the way. I'd always try to use round numbers.
Would round be 320mm and 430mm instead of 317 and 429? Do you split in 5mm increments too? I'm really curious about this.
On Tue, 21 Jul 2020 02:13:56 +0100, Cydrome Leader <presence@mungepanix.com> wrote:
In sci.electronics.basics Commander Kinsey <CFKinsey@military.org.jp> wrote: >>> On Thu, 16 Jul 2020 08:30:20 +0100, Cydrome Leader <presence@mungepanix.com> wrote:
In sci.electronics.equipment Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Sun, 12 Jul 2020 20:21:10 +0100, Tom Gardner <spamjunk@blueyonder.co.uk> wrote:
On 12/07/20 19:01, Pimpom wrote:
On 7/12/2020 11:15 PM, Commander Kinsey wrote:
On Fri, 26 Jun 2020 05:23:31 +0100, Cydrome Leader <presence@mungepanix.com>.....<snip>........
wrote:
In sci.electronics.equipment Pimpom <nobody@nowhere.com> wrote: >>>>>>>
My mechanical slide caliper has a resolution of 0.001 inch. This >>>>>>>>>> means that it can display measurements with a precision of 1 mil, >>>>>>>>>What if your caliper had a resolution of 1 mil +/- 3 counts on the last
digit?
In America, what is a "mill"? In the UK, it used to mean a thousandth of an
inch, but people use it to mean a millimetre nowadays.
It's not a mill. It's mil - single l. It means, and has always meant, a >>>>>>> thousandth of an inch. It's not an Americanism.
In the UK "mill" means millilitre.
If you want to refer to fractions of an inch, then
it is /always/ "thou", i.e. thousandths of an inch.
In the UK "mil/mill" /never/ means 0.001".
Yes it does. My neighbour's a tradesman (in Scotland) and says
"mill/mil" (I don't know which as they sound the same in speech) as
shorthand for millimetre. As in "that kitchen unit is 600 mill wide". >>>>> Since we don't use inches for such things in the UK, there's no
confusion.
The context there is key too. While I'd not measure a countertop or
whatever in millimeters, it would make no sense that anything in a kitchen >>>> would be measured thicknesses of paper.
We (in the US) use "guage" for wire
Isn't that really hard to work out? We use cross sectional area in mm. Which is really easy to imagine. With the added bonus that a higher number is thicker. It's also pretty handy as a rough guide that 1 square mm carries 10 amps.
Not really. If you can only count with your fingers you probably aren't
building anything impressive to start with. The entire fallacy of "metric
is easy, base 10, duh" is just bullshit. Check dimensions of anything
designed by people that don't know what fractions are. There are tons of
weird numbers like 13.1mm and so forth. It's no different than 1-1/8th
inches.
Yes it ism because the number system works in 10s. So if the
measurements do too, it's simpler to calculate, especially when you get
1/2, 1/4, 1/8, 1/16, 1/32 inches. What's 1/4 inch + 1/16? And even
worse, how many feet in 197 inches?
and sheet metal.
Seriously? Wow. Why would you not measure a thickness in a unit of
distance?
The guage for sheet metal is sort of obnoxious. It will vary by type of
metal as well, if that makes any sense.
It's daft for wiring aswell. I can immediately visualise what a 6mm^2
cross section of wire is like, and know how much current it will take.
We also use "guage"We use microns.
for measuring really thin stuff like plastic films. In the last case, it's >>>> a completly different unit, but with proper context won't confuse anybody. >>>
how many microns thick is your plastic trash bag?
Not enough. They've now made them so thin that everybody ends up
tearing them or using two or three layers to stop stuff going through
them. Fucking environmentalists.
The last ones I got were
speced on the box as "0.7 mil" There's no false sense of precision there,
Mil what? Millimeters? Thousands of an inch?
like with the 610mm countertop or whatever it was.
What's wrong with bags in microns? It's the correct unit of measurement, as it's thinner than a mm. You wouldn't drive 17,000 yards, you'd state it in miles.
Question for the metric woodworkers. Does anybody cut a piece of wood to >>>> 317mm or 429mm or other off numbers when building a house or handing a >>>> door or installing a countertop?
Depends if something else is in the way. I'd always try to use round
numbers.
Would round be 320mm and 430mm instead of 317 and 429? Do you split in 5mm >> increments too? I'm really curious about this.
Not sure what you're asking here. If I'm designing something, I'll use round numbers. I just built a parrot nestbox. Funnily enough I cut the wood to 30cm, not 25 or 28.
| Sysop: | Amessyroom |
|---|---|
| Location: | Fayetteville, NC |
| Users: | 65 |
| Nodes: | 6 (0 / 6) |
| Uptime: | 00:56:01 |
| Calls: | 862 |
| Files: | 1,311 |
| D/L today: |
10 files (20,373K bytes) |
| Messages: | 264,187 |