I got a bag of these in a box lot of "amplifier parts" on eBay. What are they? The only measurement I can get with my meter is 10M ohms...

mystery component

  • \$\begingroup\$ No markings or writing on the component? \$\endgroup\$ Apr 8, 2020 at 5:11
  • \$\begingroup\$ None just the orange dot on each. \$\endgroup\$ Apr 8, 2020 at 22:57

2 Answers 2


It appears to be a fried Metal Oxide Varistor or Thermistor.

  • \$\begingroup\$ MOV sounds right. Never installed, so not fried. But I believe they have a shelf life. \$\endgroup\$ Apr 8, 2020 at 5:48
  • \$\begingroup\$ It appears so! The original colour may have been orange. Shelf life is not an issue. Degradation occurs only due to voltage spikes encountered in operation. \$\endgroup\$
    – vu2nan
    Apr 8, 2020 at 6:27

As vu2nan says it is most likely a MOV (metal oxide varistor) which will have a high resistance until a large voltage is applied across it.

The exact voltage is hard to tell without a power supply that can generate a sufficient voltage; possibly above 200-300 volts, as it is often used to protect the input of AC line circuits.

Read more here: https://en.m.wikipedia.org/wiki/Varistor


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