Power supply for gas discharge tubes
MRMILSTAR, Sun Sept 29 2019, 03:45AMI bought several gas discharge tubes at a swap meet recently. They contain various gases such as krypton, helium, argon, and nitrogen. Each tubes is made of glass and is about 12 inches long and 0.5 inch wide. There are leads protruding from each end. What is the best way to power these tubes to get good brightness without burning them out? What is a good voltage and current? I have on hand a NST and MOTs. I also have a variac to control the voltage if necessary. I also have various tesla coils but I wanted a power source independent of those.
Re: Power supply for gas discharge tubes
Patrick, Sun Sept 29 2019, 08:05PM
these sound like student lab demonstration tubes. they have a standup box they slide into ad the ends. i think a current limited HV source like an NST would work, but current im not sure ...
do they look like those ?
Patrick, Sun Sept 29 2019, 08:05PM
these sound like student lab demonstration tubes. they have a standup box they slide into ad the ends. i think a current limited HV source like an NST would work, but current im not sure ...
do they look like those ?
Re: Power supply for gas discharge tubes
MRMILSTAR, Sun Sept 29 2019, 08:40PM
Not exactly. Mine don't have that pinch in the middle and don't have a filament so I assume that they are cold cathode tubes.
MRMILSTAR, Sun Sept 29 2019, 08:40PM
Not exactly. Mine don't have that pinch in the middle and don't have a filament so I assume that they are cold cathode tubes.
Re: Power supply for gas discharge tubes
Patrick, Mon Sept 30 2019, 03:05AM
ive never seen one with a filament, they just glow like a neon "OPEN" sign in a store front.
Patrick, Mon Sept 30 2019, 03:05AM
ive never seen one with a filament, they just glow like a neon "OPEN" sign in a store front.
Re: Power supply for gas discharge tubes
klugesmith, Tue Oct 01 2019, 11:23PM
I bet 30 mA, same as nominal value of most NST's, will be fine. Brightness will be lower on the 5 mA from a cheap CCFL inverter.
Tubes with a pinched section, like in Patrick's link, might provide higher luminance from a narrower source to facilitate viewing of the spectra.
A neon sign making class taught me that those luminous tubes are all cold cathode, and the great majority are technically fluorescent lamps.
The natural gas discharge colors, seen when glass tube is clear, are red (neon) and light blue (argon + mercury). I think other gases are rarely used (pun intended). Except in neon art, physics demonstrations, and of course flash lamps. Xenon flashlamps are normally operated with current on the order of 100 amperes, even the tiny ones in point-and-shoot cameras.
The other colors in pallete come from glass tubes that look white when "off", because of fluorescent coating.
Nominal colors are obtained with argon-mercury fill.
Same tubing gives different colors when other fill gases are used. Like the pink neon I salvaged from a movie theater the day before it was demolished, whose tubing labels have "blue" in the name.
Picture is from
klugesmith, Tue Oct 01 2019, 11:23PM
I bet 30 mA, same as nominal value of most NST's, will be fine. Brightness will be lower on the 5 mA from a cheap CCFL inverter.
Tubes with a pinched section, like in Patrick's link, might provide higher luminance from a narrower source to facilitate viewing of the spectra.
A neon sign making class taught me that those luminous tubes are all cold cathode, and the great majority are technically fluorescent lamps.
The natural gas discharge colors, seen when glass tube is clear, are red (neon) and light blue (argon + mercury). I think other gases are rarely used (pun intended). Except in neon art, physics demonstrations, and of course flash lamps. Xenon flashlamps are normally operated with current on the order of 100 amperes, even the tiny ones in point-and-shoot cameras.
The other colors in pallete come from glass tubes that look white when "off", because of fluorescent coating.
Nominal colors are obtained with argon-mercury fill.
Same tubing gives different colors when other fill gases are used. Like the pink neon I salvaged from a movie theater the day before it was demolished, whose tubing labels have "blue" in the name.
Picture is from
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