Thyratron heater supply?

imix500 · 15th March 2004, 05:03 AM

Hi, I have a JAN 5849 that I'd like to light up for demonstration purposes. Can the filament of a large thyratron such as this be driven with DC? This tube has a reservior heater as well. Normally the two need to be feed with AC that is in phase. Can both be driven with DC? I'm asking because it's available. Thanks!

Frank Berry · 15th March 2004, 09:57 AM

Is it possible that this tube is a 5948 rather than a 5849?

If so, the tube has a 6.3 volt filament. It draws about 30 amps!
The reservior heater operates at 2.5 to 5.5 volts and draws about 5 amps.

Yes, you can operate these filaments from a d.c. supply.

imix500 · 15th March 2004, 11:54 AM

That's correct, it's a 5948. I knew that it needed around 30A for the filament, and I have an old lab power supply that can supply that. That's a lot of watts, but nothing compared to what it can switch!

catrafter · 15th March 2004, 04:01 PM

I've always just stuck a small colored lamp up inside the base and illuminated the 'tube' that way. Works great and with the right lamp, you can get that cool 'hydrogen blue' look!

imix500 · 15th March 2004, 08:13 PM

That's a good idea. I've illuminated several that way as well, but this one is going to be firing for real into a 200 watt load. The tube won't even know it's there, but it should do fine to show ionization.

Sch3mat1c · 15th March 2004, 09:22 PM

Then hook 'er up and let it burn.

Hmm, 6.3V * 20A...I'll have to peek at the data sheet and see how jealous my C3J is...

Edit: can't find anything but 5949.

Tim

imix500 · 15th March 2004, 10:07 PM

It's similar, and I'm still searching for the datasheet as well. I have enough info to fire it safely, but the exact specs are always nice to have. I think the 5948's peak pulse capacity is around 50Mw, just a little higher than the C3J.

Sch3mat1c · 16th March 2004, 12:49 AM

Well the 4959 says 25kV and 500A so 1.25MW... if it's anything like it, then yep!

I'd expect more heater power given your estimate.

Would be nice to have a several kA hydrogen thy. for a quarter shrinker.

Tim

imix500 · 16th March 2004, 01:10 AM

Indeed. Although I don't think other people in my building would appreciate the equivalent of a small EMP device, niether would anything with a silicon junction.

15th March 2004, 05:03 AM	#1
imix500 Proud Union Member diyAudio Member Join Date: Mar 2004 Location: Nashville, TN	Thyratron heater supply? Hi, I have a JAN 5849 that I'd like to light up for demonstration purposes. Can the filament of a large thyratron such as this be driven with DC? This tube has a reservior heater as well. Normally the two need to be feed with AC that is in phase. Can both be driven with DC? I'm asking because it's available. Thanks!

15th March 2004, 09:57 AM	#2
Frank Berry diyAudio Member Join Date: Sep 2003 Location: Midland, Michigan	Is it possible that this tube is a 5948 rather than a 5849? If so, the tube has a 6.3 volt filament. It draws about 30 amps! The reservior heater operates at 2.5 to 5.5 volts and draws about 5 amps. Yes, you can operate these filaments from a d.c. supply. __________________ Frank

15th March 2004, 11:54 AM	#3
imix500 Proud Union Member diyAudio Member Join Date: Mar 2004 Location: Nashville, TN	Ah yes. That's correct, it's a 5948. I knew that it needed around 30A for the filament, and I have an old lab power supply that can supply that. That's a lot of watts, but nothing compared to what it can switch!

15th March 2004, 09:22 PM	#6
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	Then hook 'er up and let it burn. Hmm, 6.3V * 20A...I'll have to peek at the data sheet and see how jealous my C3J is... Edit: can't find anything but 5949. Tim __________________ Seven Transistor Labs Projects and Resources

16th March 2004, 12:49 AM	#8
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	Well the 4959 says 25kV and 500A so 1.25MW... if it's anything like it, then yep! I'd expect more heater power given your estimate. Would be nice to have a several kA hydrogen thy. for a quarter shrinker. Tim __________________ Seven Transistor Labs Projects and Resources


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15th March 2004, 04:01 PM	#4
catrafter diyAudio Member Join Date: May 2003 Location: Montana	I've always just stuck a small colored lamp up inside the base and illuminated the 'tube' that way. Works great and with the right lamp, you can get that cool 'hydrogen blue' look!

15th March 2004, 08:13 PM	#5
imix500 Proud Union Member diyAudio Member Join Date: Mar 2004 Location: Nashville, TN	That's a good idea. I've illuminated several that way as well, but this one is going to be firing for real into a 200 watt load. The tube won't even know it's there, but it should do fine to show ionization.

15th March 2004, 10:07 PM	#7
imix500 Proud Union Member diyAudio Member Join Date: Mar 2004 Location: Nashville, TN	It's similar, and I'm still searching for the datasheet as well. I have enough info to fire it safely, but the exact specs are always nice to have. I think the 5948's peak pulse capacity is around 50Mw, just a little higher than the C3J.

16th March 2004, 01:10 AM	#9
imix500 Proud Union Member diyAudio Member Join Date: Mar 2004 Location: Nashville, TN	Indeed. Although I don't think other people in my building would appreciate the equivalent of a small EMP device, niether would anything with a silicon junction.

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