black light

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

 

[Sjouke Burry]

On 11-2-2019 23:53, 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?

Checking bills for forgery.
Checking minerals for fluorescence.
Checking bedsheets for eh. you know eh...

What's inside?
Either a LED or a small fluorescent tube(got one with that).

And whence the origin of the term 'black light'?
You cannot see UV light, so they called it blacklight.
I recall days gone by, the wall posters were popular, is
that still in fashion?
?????

--
Rich

 

[Jasen Betts]

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.

 

[J.B. Wood]

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

 

[Jeff Layman]

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

 

[Andrew Smallshaw]

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

 

[Jasen Betts]

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.