Does anyone know what this thing is?

[paggerman]

I bought a box full of valves a few months ago and found this at the bottom. Can anyone tell me what it is? Is it of any use?



The metallic shank inside the glass tube has a silk screen reading "RPC Resistance Product Company, Harrisburg, PA, USA. BBV. 879 MEG 5%"

On the handle flange it says "Phillips Made in Holland Type GM 4579 1kV-30kV" and a serial number.

thanks you for your help

Jeff

[drewl]

Looks like a high voltage probe that went to a certain type of voltmeter.

I'm familiar with newer style ones that would work with Fluke meters or most standard meters.
It would attenuate the voltage you measured by 1000v so your meter could read it without getting fried.

[km6xz]

It is a high voltage probe. It is used to drop the high measuring voltage down to a proportional lower voltage that is within the range of the meter that it was intended for. The other end of the connector screws into a Philips GM 7635 VTVM from back in the early 1950s by their division in France. It could be useful if you know the input impedance of your meter or oscilloscope for measuring tube amp B+. It is rated for 30,000 volts which is overkill for a amplifier but many digital meters only measure up to 300 volts. The probe might be a 100:1 or 1000:1 divider ratio. Did you get a grey box with a large analog meter in the upper center of the panel? If so you are in luck because the combination mate a good quality vacuum tube volt meter for general measurements of AC, DC and resistance.
Vacuum tube volt meters are very useful for working on tube electronics, they handle high voltage better and have wide bandwidth for AC measurements and they can handle the acts that a probe sometimes draws from barely touching a high voltage point that often destroys a digital meter.