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  • Re: black light

    From Jasen Betts@jasen@xnet.co.nz to sci.electronics.misc on Tue Feb 12 02:14:04 2019
    From Newsgroup: sci.electronics.misc

    On 2019-02-11, rdelaney2001@gmail.com <rdelaney2001@gmail.com> wrote:
    I saw a pocket flashlight in a hardware store yesterday,
    it shines UV. Such a package is new to me.

    What is it good for?

    currency checking.
    reading UV security marks.
    curing UV-cure resin.
    erasing EPROMs.
    searching for lost flourescent items.
    making candy glow wierd colours.
    etc...

    What's inside?

    a UV light emitting diode.
    --
    When I tried casting out nines I made a hash of it.
    --- Synchronet 3.21d-Linux NewsLink 1.2
  • From J.B. Wood@arl_123234@hotmail.com to sci.electronics.misc on Tue Feb 12 06:35:19 2019
    From Newsgroup: sci.electronics.misc

    On 2/11/19 5:53 PM, rdelaney2001@gmail.com wrote:
    I saw a pocket flashlight in a hardware store yesterday,
    it shines UV. Such a package is new to me.

    What is it good for? What's inside?

    And whence the origin of the term 'black light'?
    I recall days gone by, the wall posters were popular, is
    that still in fashion?

    --
    Rich


    Hello, and not knowing the footprint of what you saw, I've got small,
    handheld a 25 year old flashlight that incorporates both a miniature incandescent bulb (like the #222 but rated at 4.8 volts) and 4" F4T5
    white fluorescent tube and uses 4 penlight batteries. A 4" UV tube,
    F4T5/BLB can be substituted and then you have a small, portable UV
    source that also doubles as flashlight. Don't know if what I have can
    still be purchased (NOS perhaps). Sincerely ,
    --
    J. B. Wood e-mail: arl_123234@hotmail.com
    --- Synchronet 3.21d-Linux NewsLink 1.2
  • From Jeff Layman@JMLayman@invalid.invalid to sci.electronics.misc on Tue Feb 12 18:43:31 2019
    From Newsgroup: sci.electronics.misc

    On 11/02/19 22:53, rdelaney2001@gmail.com wrote:
    I saw a pocket flashlight in a hardware store yesterday,
    it shines UV. Such a package is new to me.

    What is it good for? What's inside?

    And whence the origin of the term 'black light'?
    I recall days gone by, the wall posters were popular, is
    that still in fashion?

    --
    Rich

    Well over 50 years ago I bought an ex-WW2 aircraft "blacklight",
    possibly from a Lancaster. It was on flying leads, with a black-painted
    metal body about a couple of inches in diameter and long. Inside was a
    small filament bulb (I can't remember the voltage - possibly 12?). The
    front was a domed, very dark violet glass. When the bulb was on, you
    could just about see the filament in a dark room. I also had a couple of instruments from a WW2 plane. Both had paint which glowed well in the
    dark under that blacklight.

    See here <https://en.wikipedia.org/wiki/Blacklight#Uses> about 3/4 of
    the way through.
    --

    Jeff
    --- Synchronet 3.21d-Linux NewsLink 1.2
  • From Andrew Smallshaw@andrews@sdf.org to sci.electronics.misc on Wed Feb 13 15:29:27 2019
    From Newsgroup: sci.electronics.misc

    On 2019-02-12, Jasen Betts <jasen@xnet.co.nz> wrote:
    On 2019-02-11, rdelaney2001@gmail.com <rdelaney2001@gmail.com> wrote:
    I saw a pocket flashlight in a hardware store yesterday,
    it shines UV. Such a package is new to me.

    What is it good for?

    erasing EPROMs.

    One would hope not. The UV band is generally split into three, UV
    A, B and C. To erase EPROMS you need the UVC, most blacklights,
    most blacklights, especially the commodity devices for banknote
    checking, UV curing etc are UVA. UVA is what those insect killing
    lamps you see put out, albeit generally in white rather than
    blacklight form. UVC is much shorter wavelength and a massive risk
    to your eyes if exposed to it. Think the kind of masks used for
    arc welding. There is a reason EPROM erasers invariably have safety
    lock that cut out if you open the drawer when it is operating.

    a UV light emitting diode.

    Could be. Could be a small fluorescent or a filament bulb.
    --
    Andrew Smallshaw
    andrews@sdf.org
    --- Synchronet 3.21d-Linux NewsLink 1.2
  • From Jasen Betts@jasen@xnet.co.nz to sci.electronics.misc on Thu Feb 14 05:35:51 2019
    From Newsgroup: sci.electronics.misc

    On 2019-02-13, Andrew Smallshaw <andrews@sdf.org> wrote:
    On 2019-02-12, Jasen Betts <jasen@xnet.co.nz> wrote:
    On 2019-02-11, rdelaney2001@gmail.com <rdelaney2001@gmail.com> wrote:
    I saw a pocket flashlight in a hardware store yesterday,
    it shines UV. Such a package is new to me.

    What is it good for?

    erasing EPROMs.

    One would hope not
    To erase EPROMS you need the UVC,

    ok. not EPROMs then.

    a UV light emitting diode.

    Could be. Could be a small fluorescent or a filament bulb.

    I have a LED one here. It's I0 cm long so definately pocket sized.

    https://www.aliexpress.com/item/UV-Flashlight/32831334716.html
    --
    When I tried casting out nines I made a hash of it.
    --- Synchronet 3.21d-Linux NewsLink 1.2