Hi all,

Came into possession of a couple of different old lamps. Glass envelopes, approx 10cms tall, 4cms in diameter, about 10 'pins' which are prongs pointing sideways. One 'electrode/filament' only, drapped over a central pole like Xmas tree lights, continuity across two 'pins', tens of ohms.

I have put 40 volts DC (drawing less than 0.2amps) into one of them; lamp gets warm, but no 'glow'. Cannot find any info on internet, probably because I don't know what it is called. Photo sent to Brad.

My Power Supply can go to 80 volts 2 amps DC, but thought I should ask advice here first, before going too far .... don't want to destroy one of these nice old things through ignorance ....

Any ideas as to the voltage or current these things should be run at?? AC or DC .... re heating????

Im Thinking (without seeing pic) that it may be a barretter. Used mainly on AC/DC radios.

https://en.wikipedia.org/wiki/Iron-hydrogen_resistor

Ben

Hi Ben,

Base and glass envelope are very similar, but my centre electrode/pole is way more complicated. Think of old sailing ship mast with spars sticking out in several directions with the wire running up and down connected to the end of the spars .... a photo is worth a thousand words.

It is indeed a barretter and with a P base. It is definitely worth keeping. Whilst they did have other uses, barretters were used mainly for current limiting.

Mmmm ... okay .... something 'new' every day. Heard of them, but never seen one. I will do some googling tomorrow.

Thanks guys!!

Its actually an Iron Filament in an atmosphere of Hydrogen. The Americans always have trouble with European spelling & names, likely think its a gun anyway, so they call them Ballast Tubes.

You as Brad has suggested commonly find them in series with the filament string on AC/DC radios, although I have seen one in a German pH meter, likely to hold the heater current constant whilst a VR tube does the same to the HV. That was the sort of apparatus that you did not need to drift.

You may find info on Franks Electron Tube Pages?

Often there is more than one filament. Its a resistor so AC or DC is not the issue. In filament string, where filaments are cathodes, then it matters. All of the heater / filaments will have the same current draw.

AKA: "Hot Wire Barretter"; Watch the spelling

Marc

Okay ... these are the closest matches to what I have ......

Image Link
Image Link

mmmm .... what to do with them ......?????

I suspect that it is a C1 as they were pretty common here in AC / DC radios as indicated.

As it looks like it may be functional, tossing it is not an option and will likely radiate bad Karma.

See if you can pick up a number seeing that you now know where C1 has its. Cooling the tube & breathing on it often reveals the number as does certain angles of light. C1 data is available.

Peter Pan 1938 Model 576 AC/DC used one. Looks like all Philips valves in it.

Marc

Re my Post #7 above .... numbers on Barretters are

First web page reference ................. Made in Holland C A 73
Second web page reference .................. Stabilovolt logo H85-25?/60 a3?

Starting to find some info on second Barretter eg 85 to 255 volt either 0.06 or 0.08amps.

The data sheets for C1 and thousands of other valves are here https://bms.isjtr.ro/sheetsC.html

They will show you how they are applied.

Marc

Thanks for that .... hadn't seen that site.