1
Beginners / Re: Checking for noise in resistors
« Last post by floobydust on Today at 06:59:42 pm »From the era of tube gear, many signal tracers have a "NOISE" mode switch built-in. Example Heathkit IT-12.Yeah, that and the more capable T-3 are the Heathkit units I talked about in a previous post in this thread. It is unobtainium here in Europe at least at a reasonable price.
That applies high voltage bias to the probe about 115VDC/1.7mA and with the audio amplifier you can listen to the result.
A noisy resistor or capacitor with bad dielectric can be flushed out. It was a common problem in the day.
That was more or less the circuit I was trying to make, albeit somewhat modernized, i.e.: no tubes
It's not hard- take an LM386 amplifier board $1.50 and run that with added blocking cap+protection diodes, and low noise HV power supply.