Question regarding the identification of a component

The marking suggests that like the other capacitor it's a Sprague component. You are probably aware that Sprague was known for capacitors, but that doesn't prove it isn't a thermistor or surge protection component of some kind. Image search finds nothing with similar markings. Try applying some volts and see if you get any amps. Does the converter work without it? What was the reason for disconnecting it? How many of these components are there and what are they connected to?

Maybe "41C" indicates the transition temperature for a PTC?

That's an old stype disc ceramic capacitor. 10nF, 3kV, Z5U material

That's an old style ceramic disc capacitor. 10nF/3kV, Z5U material.

The other one seems to be a varistor

Seems pretty skinny for a >1 kV varistor, so I expect it’s a house part number.

Cheers

Phil Hobbs

The front side markings do suggest a 10nF capacitor with Z5U dielectric and 3kV voltage rating. A measured capacitance of 8nF is consistent with that, as the Z5U dielectric is very variable with voltage and temperature as well as ageing - not to mention initial tolerance which might be +/- 20%. John

John R Walliker schrieb:

It seems that my post wasn't clear enough. There are two different components: one is clearly marked as a 10 nF capacitor, while the other has this cryptic marking.

Reinhard

Edward Rawde schrieb:

Tested the part with a 2 megohm series resistor at 3 kV (with a capacitive voltmeter in parallel): no problem.

Yes.

To take the best possible photo.

Just this one. One side connected to ground, the other side is connected to the HV line (in parallel with the 10 nF capacitor).

Regards

Reinhard

The part behaves in no way as sort of resistor.

Yes, that is the part shown in the first photo.

Unfortunately, it doesn't behave like one (0 ... 3 kV).

Unless it has failed, open-circuit?

Chris

Yes and no. Multitester says: 7,8 nF capacitor. But a capacitor should just be open circuit, otherwise it's broken. On the other hand I doubt that a PTC/NTC is connected to ground and a 1 kV line.

Reinhard

Sorry, I was still in VDR territory when suggesting open circuit.

Chris

Don't worry! I just referred to the above mentioned PTC.

I just tested a S20K300 varistor manufactured by EPCOS in series with a 33 k resistor: limiting startet at approx. 420 V, max. voltage across this varistor was about 460 V. (Multitester said: 820 pF capacitor ...). So I think an "open circuit" test result doesn't prove a 3 kV varistor is broken: my test voltage is limited to "only"

Regards

Reinhard

Does the geiger counter have a model number or brand name?

RL?

The mfr mark 'sideways 2 or ~ in an oval' shows up on a few ceramic disks in my junk collection.

They all have roughly conventional markins, in pF with a tempco and voltage.

Without those markings, they would have been scrapped, if they didn't show other useful characteristics, like voltage breakdown or spark gap(there are one of those with that marking).

RL

Logo could be a variation of Nihon Inter Electronics.

If 'Nihon' is the basis of the company logo, it could be any number of companies of Japanese origin. Nihon = Japan.

These older logos are not easy to track.

Your cap logo has an additional " I " vertical.

RL