What component is this?

[mvno_subscriber]

I found these components the other day while looking for NTC thermistors. I grabbed a couple since the shape was similar, and thought maybe the bars indicated resistance at room temperature.

However, both of them act as an open circuit - no connection between the legs. Capacitor tester reports 0nF.

Anyone know what these are? The discs are a little less wide than my thumb.

[pcprogrammer]

I think they are capacitors. The left one 36pF and the right one either 360pF or 3.6nF, but since your tester reports 0nF it is 360pF, assuming your tester does not measure these low values.

This based on what the following site shows.
https://www.electronics-tutorials.ws/capacitor/cap_5.html

[PA0PBZ]

It really doesn't look like any capacitor I've ever seen, so if they are not NTC's my guess would be varistors (VDR's) so you would need a high voltage to get it to react.


Edit: look at this: https://www.ebay.co.uk/itm/402363750824

Edit 2: VDR Color code: https://frank.pocnet.net/other/Philips/ColourCodeRC1966.pdf

Not your colors but maybe different manufacturer/series.

[SiliconWizard]

Yes I would also say these are varistors.

[mvno_subscriber]

Thanks! Yes, that seems to match. Tried to measure pF capacitance, got 50-70pF so that rules out it being a capacitor (at least based on the color codes).

Wondering what interesting projects I could use these in

[tigrr]

Anyone know what these are? The discs are a little less wide than my thumb.

Even by their appearance it is clear that these are varistors. Typical for old-type varistor housings, a disk with a rough surface and soldered terminals to the center. Again, all varistors are "quite thick".

[timeandfrequency]

Anyone know what these are? The discs are a little less wide than my thumb.

Even by their appearance it is clear that these are varistors. Typical for old-type varistor housings, a disk with a rough surface and soldered terminals to the center. Again, all varistors are "quite thick".

... and have some residual/parasitic capacitance.

I would also say that the pictured parts are rather VDR's

I measured two VDRs found in the scrap drawer (aka 'mixed parts repository')  :
250 VAC VDR white  (maybe Epcos) : 410 pF
60 VAC VDR S&H  : 1nF

[tigrr]

Even by their appearance it is clear that these are varistors. Typical for old-type varistor housings, a disk with a rough surface and soldered terminals to the center. Again, all varistors are "quite thick".

I can't find their color code marking yet...

[tigrr]

Here is another example of an old VDR from one of the auctions, they also have color code marking. The color of the stripes is orange, black, brown.

[tigrr]

I measured two VDRs found in the scrap drawer (aka 'mixed parts repository')  :
250 VAC VDR white  (maybe Epcos) : 410 pF
60 VAC VDR S&H  : 1nF

410 pF and 1 nF - these are quite large capacitance values ​​compared to the example above.

[timeandfrequency]

I measured two VDRs found in the scrap drawer (aka 'mixed parts repository')  :
250 VAC VDR white  (maybe Epcos) : 410 pF
60 VAC VDR S&H  : 1nF

410 pF and 1 nF - these are quite large capacitance values ​​compared to the example above.

It is certainly manufacturer and technology dependant.
Best verification might be performed if you could have access to a semiconductor analyser (something like a Tektronix 576 or 577, or similar TE)

[PwrElectronics]

Was going to say this, varistors.

We used to use these for transient protection at my company.  Most commonly for clamping against load dump on 12v automotive power inputs but the ones we used were just marked with the p/n and voltage rather than color codes.  Also have seen them used on 120/240V AC power inputs for spike clamping, etc.

[tigrr]

I grabbed a couple since the shape was similar, and thought maybe the bars indicated resistance at room temperature.

Here's what I found on the color code marking of VDR and NTC. This is the Philips marking of the 1966 standard. VDR in the upper left corner, NTC in the right.

But! It is not yet entirely clear how to decipher the varistor ratings using the tables. And, this especially concerns the second black and white table... What color codes are meant there? If anyone knows, please write!