So...
What is the difference between a gas discharge regulator tube, and a gas discharge "spark gap"?
Ok well, I am jesting a little bit, I realise a spark gap is used kill an over voltage condition - I have a couple that might be useful for protection of OPT primaries.
But could such a gas filled spark gap, be used as a reference, or voltage stabilizer? (I've never seen a real tube voltage reference, by have loads of spark gaps!)
Or are they just too noisy? (Which is my suspicion)
What is the difference between a gas discharge regulator tube, and a gas discharge "spark gap"?
Ok well, I am jesting a little bit, I realise a spark gap is used kill an over voltage condition - I have a couple that might be useful for protection of OPT primaries.
But could such a gas filled spark gap, be used as a reference, or voltage stabilizer? (I've never seen a real tube voltage reference, by have loads of spark gaps!)
Or are they just too noisy? (Which is my suspicion)
Attachments
A real tube voltage reference is something among the lines of 85A2. Those are stable within 0.1% long term at 3mA.
Last paragraph---correct. (#1 post )--collision of electrons /high energy levels .
OTOH--- the first transmitters were ----spark gap (un-modulated ).
OTOH--- the first transmitters were ----spark gap (un-modulated ).
The Gas Discharge Tubes (GDT's) made for lightning and other surge suppression are designed to eat a HUGE overload without exploding. It may need considerable recovery time before being capable of eating another. The strike over voltage may vary considerably from strike to strike, with temperature, and even ambient light.
Gas regulator tubes are optimized for constant operating voltage. The arc strike voltage may still vary considerably with temperature and ambient light conditions, and they will fry, or explode if overloaded.
Gas regulator tubes are optimized for constant operating voltage. The arc strike voltage may still vary considerably with temperature and ambient light conditions, and they will fry, or explode if overloaded.
Something with nails on the head, en fin i digress.
Gas regulator tubes come in two varieties, tubes like the 0A2 that can operate from 5-30mA and will regulate between 145-155V (brand dependant YMMV). And tubes such as the previously mentioned 85A2 that are references in the truest sense in that they provide low drift voltage, but have poor initial voltage tolerance.
The Russians made all kinds of pin compatible 7 pin regulator tubes that are analogous if not direct replacements for the western device. These are fine quality devices available for one or two euro each.
Gas regulator tubes come in two varieties, tubes like the 0A2 that can operate from 5-30mA and will regulate between 145-155V (brand dependant YMMV). And tubes such as the previously mentioned 85A2 that are references in the truest sense in that they provide low drift voltage, but have poor initial voltage tolerance.
The Russians made all kinds of pin compatible 7 pin regulator tubes that are analogous if not direct replacements for the western device. These are fine quality devices available for one or two euro each.
That's what gave me the impression they would be noisy, thanks for confirming.
I use these gas spark gaps at work for the protection of current transformers, the modern ceramic lightening and surge arrestors dont seem to be robust enough at least the easily available ones.
Cool. I wont be trying to use one as a screen reg then 😀
Last edited:
Gas discharge regulator and reference tubes are optimized to give the most stable and reproducible voltage possible: the gas mixture, electrode materials, shapes and distances and gettering are all designed such that the voltage is as predictable as possible. A spark gap overvoltage protector is designed to handle a huge energy without exploding.
If you want to know the ins and outs of gas discharge regulator and reference tubes, check if there is a library where you can borrow G. F. Weston, Cold cathode glow discharge tubes, London ILIFFE Books, Ltd., 1968.
If you are specifically interested in their noise, these articles are interesting: A. van der Ziel and E. R. Chenette, "Noise and impedance measurements in voltage regulator tubes", Physica, vol. XXIII, 1957, pages 943...952 and J. F. Dix and K. B. Reed, "Cold cathode discharge tubes - Impedance and noise properties", Electronic Technology, vol. 39, no. 1, January 1962, pages 31...37. You can also find their main conclusion in section 4 of this freely downloadable article: https://linearaudio.net/sites/linearaudio.net/files/03 Didden LA V13 mvdg.pdf
If you want to know the ins and outs of gas discharge regulator and reference tubes, check if there is a library where you can borrow G. F. Weston, Cold cathode glow discharge tubes, London ILIFFE Books, Ltd., 1968.
If you are specifically interested in their noise, these articles are interesting: A. van der Ziel and E. R. Chenette, "Noise and impedance measurements in voltage regulator tubes", Physica, vol. XXIII, 1957, pages 943...952 and J. F. Dix and K. B. Reed, "Cold cathode discharge tubes - Impedance and noise properties", Electronic Technology, vol. 39, no. 1, January 1962, pages 31...37. You can also find their main conclusion in section 4 of this freely downloadable article: https://linearaudio.net/sites/linearaudio.net/files/03 Didden LA V13 mvdg.pdf
So a cold cathode reg is more akin to a neon than a spark gap? I know some neons were made to have a tight ignition/sustain voltage tolerance, but not most neons.
Has anyone ever used a neon when very low screen currents are expected? Say less than 0.5mA.
Thanks Marcel for the links.
It is more of an academic interest, I dont plan on sourcing any valve regulators; it is more that I am interested in anything that can be used to regulate the screen voltage.
I've used voltage dividers, zener regulators, I just wanted to see if there was anything I already possess that I could pervert into a screen regulator.
Neons are likely a no no, as well (shame, I have plenty), so I'd guess the next step for me is HV BJT/FET regulator for Vg2 then also for HT....and i suppose then, also for Vg1....
Has anyone ever used a neon when very low screen currents are expected? Say less than 0.5mA.
Thanks Marcel for the links.
It is more of an academic interest, I dont plan on sourcing any valve regulators; it is more that I am interested in anything that can be used to regulate the screen voltage.
I've used voltage dividers, zener regulators, I just wanted to see if there was anything I already possess that I could pervert into a screen regulator.
Neons are likely a no no, as well (shame, I have plenty), so I'd guess the next step for me is HV BJT/FET regulator for Vg2 then also for HT....and i suppose then, also for Vg1....
Last edited:
I expect that should work, but the voltage will not be as predictable as with an 85A2 or similar reference tube. The white noise should still follow the equation in the link I gave, maybe 1/f noise will be worse.
Haven't done it myself, but it's been done lots before. These have been used as screen stabilizers for small signal pentodes.
Depends on what you mean by that. Those small neon tubes used for panel lights can definitely be used as voltage regulators, though they can't handle the current of a 0A2 or similar VR tube. You could use the panel neons as a voltage reference for an active screen regulator (hollow state or solid state) as the current demand isn't very high. The main problem is that these panel neons are getting to be unobtanium since the advent of LEDs.
The one thing you don't want to do is parallel any gas discharge device with a noise suppression capacitor since there is a negative resistance characteristic that will turn in into an oscillator. (The reason why spark gap transmitters worked.) The noise is more like white noise and much less objectionable than the reverse current noise through a Zener.
By the way, a neon lamp with a too large capacitor in parallel with it will either start blinking or self-destruct at ignition, but the same holds for a glow discharge reference tube. Edit: I see that Miles wrote something similar while I was typing this.
Miles and Marcel, thanks!
I have 50 or so Soviet neons (INS 1) so it may be worth a shot, 2 or three in series should give about 140V and 210V. I have some MES 130V neons also, and some 24V too.
I was going to use them to try and build a simple saw tooth generator, then repeat for a unison saw tooth generator for a ribbon controlled instrument
I have 50 or so Soviet neons (INS 1) so it may be worth a shot, 2 or three in series should give about 140V and 210V. I have some MES 130V neons also, and some 24V too.
I was going to use them to try and build a simple saw tooth generator, then repeat for a unison saw tooth generator for a ribbon controlled instrument
Last edited:
You probably know this, but with a string of series-connected neon lamps, you can reduce the ignition voltage with some large parallel resistors.
String of two: give one a 1 Mohm or so shunt resistor and the other not. At start-up, all voltage will initially drop across the one without a shunt resistor until it ignites, and then the voltage will divide between the neon lamps, but with the one that's already ignited running at its maintaining rather than its ignition voltage.
String of three: shunt the bottom lamp with a large resistor and the series connection of the bottom two lamps with another large resistor.
String of two: give one a 1 Mohm or so shunt resistor and the other not. At start-up, all voltage will initially drop across the one without a shunt resistor until it ignites, and then the voltage will divide between the neon lamps, but with the one that's already ignited running at its maintaining rather than its ignition voltage.
String of three: shunt the bottom lamp with a large resistor and the series connection of the bottom two lamps with another large resistor.
I bought a box of some small russian neon indicator lamps. They seem to ionize at an extremely low voltage, like 45.
I have INS-1 Soviet neons which are just dot neons with a lens on the front.
The data sheet ignition is something like 65 to 90V (just looked it up), sustaining is somewhat lower about 55V.
Max current less than 0.5mA.
I'll have to root through the boxes and find them again!
They are neon orange.
And Thank you Marcel, I didn't already know that! Ok So I probably would've tried something like that eventually, but that was a very helpful tip
The data sheet ignition is something like 65 to 90V (just looked it up), sustaining is somewhat lower about 55V.
Max current less than 0.5mA.
I'll have to root through the boxes and find them again!
They are neon orange.
And Thank you Marcel, I didn't already know that! Ok So I probably would've tried something like that eventually, but that was a very helpful tip
Last edited: