This circuit uses a diode as a radiation sensor. The operational ones are old because the publication is from the 80's, but modern low voltage equivalents can be tested.
This oscillator with signal amplitude adjustment generates a 6.5 Hz signal with the values of the...
We found this circuit for guitar training in an English documentation from 1989. The components are from...
This circuit was found in a Hands On Electronics from the 90s. The circuit does not need a...