Sciencemadness Discussion Board - miniture neon lamps

miniture neon lamps

alive&kickin - 5-12-2015 at 06:57

Another freebie for the asking. I have some (hundreds) of small neon lamps and a LED bar display (first come first serve on that one). The only real use I've found for these is a pilot light for any kind of electronic project, although you may have something else in mind. As an example, I used a current limiting resistor encased in some heatshrink as a power on indicator. Always free. U2U me.

Metacelsus - 5-12-2015 at 15:57

What striking and sustaining voltage do the neon glow tubes use?

alive&kickin - 5-12-2015 at 16:33

I've used these on circuits from 80 to 120 volt, don't know what the full range is. I can always send enough for a little experimenting.

CharlieA - 5-12-2015 at 18:36

So these samples are available from.....?

Harristotle - 6-12-2015 at 06:36

Ah neon lamps, I love 'em.

Great for calibrating spectroscopes,
they have teeny amount of thorium in them, to make them strike (once wasted a summer holiday trying to hack them into cheap geiger tubes).

Not bad for crude, hv static arrestors for a high impedence fet amplifier, put a few in series to make a hv voltage regulator for a geiger tube SB3, 3 buck variety, and a camera flash hacked up and some big resistors.
If you need a cheap 20 gig ohm resistor that runs under 70 volts, well they're good for that too!

Bias one just under striking voltage, lay parallel on a metal or very thin glass plate and it will glow when you bring your finger next to it (remember the old fashioned lift switches/lights - capacitive touch switch!).

You can even make an oscillator out of a pair of them, if I recall correctly:

+ve
|
o ...................................... neon
|----------|
= ......... o ...................... capacitor neon
|----------|
|
-ve

(please ignore the dots, theyre to make the spacing work in ascii art)

various sizes of resistor can go in series with the neons to extend the time of the flashes.

Or if you are really radical, dip a glowing neon into a molten sodium nitrate salt (or other low temp salt). You will probably get some free electrons in there, and if done below the melting point of your flint glass envelope, you should after a while get a sodium metal silvering. Remove neon, make one metal electrode cold by dipping in iced water and the envelope warm, and you should be able to make a sodium metal photocell.

The last is one I haven't tried - it is a modification of Shakashiri's sodium metal electrolysis of of light globe via thermionic emission of electrons, but I can't see why it wouldn't, given that free electrons and Ne+ ions exist in the evacuated neon lamps.

Have a nice day.
H.

The Volatile Chemist - 6-12-2015 at 15:27

Harristotle, that's an interesting schematic. I'll have to try it, as I have two tiny neon lamps of my own...

Varmint - 6-12-2015 at 17:23

Careful when using these, they exhibit classic negative resistance once struck. That means a series resistor is absolutely required, and that resistance needs to be quite high, aim for 400 to 500uA.

An interesting experiment is to power it just below the empirically determined strike voltage in a dark area, then shine a red LED at it. The red led is just enough extra excitement to cause the neon/argon mix in the tube to strike.

The Volatile Chemist - 12-12-2015 at 15:00

Very interesting. Perhaps a laser pointer would work too, I'll have to try...

alive&kickin - 13-12-2015 at 07:05

CharlieA, these samples are available from.......me. Not quite sure what you mean by that, but it's just a bunch of lamps I've had laying around for awhile. Available to anyone that wants some. Easy to give away when you have hundreds. Like all I put on here for those in a pinch, free item including postage. I know a lot of younger people don't have the money to be buying everything they want or need, so why not help them out when possible.

CharlieA - 13-12-2015 at 14:46

Quote: Originally posted by alive&kickin

CharlieA, these samples are available from.......me. Not quite sure what you mean by that, but it's just a bunch of lamps I've had laying around for awhile. Available to anyone that wants some. Easy to give away when you have hundreds. Like all I put on here for those in a pinch, free item including postage. I know a lot of younger people don't have the money to be buying everything they want or need, so why not help them out when possible.

Thanks for the info. You are certainly generous in helping others out. I was just curious where the neon lamps might come from. I am fortunate that my brother-in-law is a retired electrical engineer, and loves building stuff. Currently, he is working on a power supply for electrolysis, and an electronic controller for a cheap toaster oven to convert it into a decent drying oven.

Keep giving others a helping hand. I admire your attitude; it's refreshing.

Charlie

alive&kickin - 13-12-2015 at 23:25

CharlieA, if you would like to pass a few on to your brother-in-law, I'd be more than happy to send some your way. I guess that goes for everyone else, if you know someone else that might want or could use some, let me know.

Texium - 14-12-2015 at 18:02

I received my neon lamps today. Asked for 3, received 12. Very generous! Thank you alive&kickin.
Now I have a sample of neon for the ol' element collection, and a bunch of extra ones to play around with. I haven't tried lighting one up yet though, as I don't have a safe power supply with that much voltage.

The Volatile Chemist - 16-12-2015 at 17:52

Quote: Originally posted by zts16

I received my neon lamps today. Asked for 3, received 12. Very generous! Thank you alive&kickin.
Now I have a sample of neon for the ol' element collection, and a bunch of extra ones to play around with. I haven't tried lighting one up yet though, as I don't have a safe power supply with that much voltage.

...Does anybody? My mid-voltage PSU is a Computer PSU with a nice piece of non-insulated Cu wire connected to the proper pins, hooked to two carbon rods (till my Dad stepped on one....).

IrC - 16-12-2015 at 23:19

Snap eight 9 volt batteries together in a series string + to - and so on (72 volts) and use in series with around 33 to 100K and the neon lamp. Cap in parallel with neon to make a relaxation oscillator flasher, vary R and C for speed, brightness, etc., just don't go too low for R. For steady light without the capacitor figure R to stay below 40 milliwatts or so. Typical neons should light from 55 to 65 volts, lower if built with an internal radiation source. You can separate a 9 volt snap into 2 halves to easily connect the ends of the battery string. A few more batteries to up the voltage for increased brightness but calculate all values avoiding going over 2 ma or about that. Overloading the batteries will drop the voltage not to mention reaching a point where damage to the lamp can occur. In any case you now have a supply that can bite but is much safer, simpler, and cheaper than building a supply.

woelen - 17-12-2015 at 00:58

A very simple power supply is described here:

http://woelen.homescience.net/science/physics/misc/simple-ps...

Be careful with the thing, especially with the el-cheapo version.

Neon lamps can be used in nice experiments, one can make nice oscillators with them. The power supply, described in the page above, is perfectly suitable for feeding the oscillator. Read the section about the neon bulb relaxation oscillator:

http://woelen.homescience.net/science/physics/exps/relaxatio...

j_sum1 - 6-1-2016 at 17:24

Neon bulbs arrived yesterday. A dozen of them. They will be good in the element collection.
I intend to get something like this to run them. Will it be suitable?

Thanx so much, alive&kickin!

[Edited on 7-1-2016 by j_sum1]

Harristotle - 6-1-2016 at 21:04

Hi J_sum1,
they should work, but use a big resistor 20kohm or better.

Or if you are truly cheap, you can make an old relay clacker and power them from the back emf and a 9v battery ...

Cheers,
H.

The Volatile Chemist - 12-1-2016 at 13:26

Wow, that's quite a simple circuit! Going to check it out - if my only relay isn't already broken