Aside for techies only: neon s'driver technicalities

[JohnW2]

This will only of be of interest to (some) techies. In another thread (( here )...

For what it is worth a neon in total darkness requires a much higher voltage to strike. Photons ( from the light ) reduce the voltage needed for the neon gas to ionise and start conducting. I haven't investigated but I wonder if the neons in screwdrivers would strike at 230 volts in a very dark room.

I may be wrong, but I must say that I was under the impression that the AC striking voltage for a typical neon glow tube never rose to appreciably above 100V, even in total darkness. I haven't been able to find any data sheets which are very helpful about this - most seem to quote only the maximum striking voltage 'under light conditions' (no details!) of around 65V for AC.

I may try some experiments - do you have any idea how long it takes for the effects of photoionisation to go away (i.e. how long I have to leave it in the dark before doing the tests)? I suspect that the ionisation is probably very short-lived, so that the ions disappear very quickly after removal from light, but I'm not sure.

Kind Regards, John