Photosensitive Neon Bulb Effect?

[Sephiroth]

Just come across a bizzare effect on another SSG configuration I am trying out.

The neon bulb across the emmiter and collector lights (very dimly) while the charging battery is connected (the battery is still charging very well by the way) but the neon bulb only flickers when exposed to a bright light.

I have a halogen desklamp above the "motor" about 1.5m aways so heat shouldn't be a significant factor. But when I put my hand (or anything) between the light so that the shadow falls on the bulb it doesn't glow at all. If I turn off the halogen it doesn't glow either.

Little bit puzzled... any chemists out there know if Neon's conductivity is photosensitive?

[amigo]

Speaking of bizzare effects I had a NE-2 dimly light up every time I touched part of the circuit (not sure if it was E or C of the transistor). I must add that there was no power connected at the time (battery off), as far as I remember. I thought "what the..." but nothing more of it and moved on.

I have been kicking myself ever since for not recording the exact setup and being able to repeat the effect. At the time I used this pancake style coil (primary next to secondary, instead of bifilar) and several times later I tried to reproduce it without any success.

Sounds like an urban legend I know, but I was sober and coherent when it happened so I know it was real. Further more it was night and that's how I was able to see the NE-2 dimly light up.

[dambit]

Hi Seph,

Are you using the blue neons, cos I was thinking that the phospor coating inside the bulb could be reacting to one of the wavelengths the halogen puts out.

Cheers,

Steve.

[professor]

Neon bulb lights up

It takes about 70 volts dc to light up a Neon NE2 Bulb.
However RF will light it at much less.
Is the Halogen Light powered directly by your house current or is it using some kind of step up transformer (Switching Supply) that may excite the Neon Gas and your circuit is just the Ground or antenna?
Try shielding it with conductive but transparent wire mesh (Mosquito Screen)
grounding the mesh.
professor

Just come across a bizzare effect on another SSG configuration I am trying out.

The neon bulb across the emmiter and collector lights (very dimly) while the charging battery is connected (the battery is still charging very well by the way) but the neon bulb only flickers when exposed to a bright light.

I have a halogen desklamp above the "motor" about 1.5m aways so heat shouldn't be a significant factor. But when I put my hand (or anything) between the light so that the shadow falls on the bulb it doesn't glow at all. If I turn off the halogen it doesn't glow either.

Little bit puzzled... any chemists out there know if Neon's conductivity is photosensitive?

[Sephiroth]

It takes about 70 volts dc to light up a Neon NE2 Bulb.
However RF will light it at much less.
Is the Halogen Light powered directly by your house current or is it using some kind of step up transformer (Switching Supply) that may excite the Neon Gas and your circuit is just the Ground or antenna?
Try shielding it with conductive but transparent wire mesh (Mosquito Screen)
grounding the mesh.
professor

It's definately the light that is causing it. I just have to cover the halogen bulb or turn the lamp around to stop it but the transformer is still in direct "line of sight".

Dambit - The neon is a standard clear wire ended NE-2

Amigo - that sounds cool would be nice if we could light bulbs just by touching part of the circuit! Could it possibly be due to a static charge like when you drag your feet on the carpet?

[vmike]

An ne-2 neon lamps firing voltage is 92 volts but will fire at 70 volts due to the miller effect. Introducing additional capacitance outside of the lamp lowers the internal capacitance and also the breakdown voltage. I've made gamma radiation detectors using this principal, bias the lamp just below the firing point and the introduction of gamma radiation will fire the lamp. Static electricity will also fire the lamp biased in this manner. So, you have a couple of possibilities for this behavior.

mike

[professor]

NE2 Bulb

Hi Vmike
You might be interested in this Article
Neon Quench Circuit

An ne-2 neon lamps firing voltage is 92 volts but will fire at 70 volts due to the miller effect. Introducing additional capacitance outside of the lamp lowers the internal capacitance and also the breakdown voltage. I've made gamma radiation detectors using this principal, bias the lamp just below the firing point and the introduction of gamma radiation will fire the lamp. Static electricity will also fire the lamp biased in this manner. So, you have a couple of possibilities for this behavior.

mike