This voltage-controlled oscillator was found in a 1965 Electronic Design. Transistors are from the time, and modern equivalents can be tested.
Found in an Electronic Design from the 90's, this circuit uses common components. The circuit is...
When the sensor receives light, the relay closes its contacts and remains so even after the light...
This circuit produces pulses of 90 V at intervals that can reach 5 minutes. The circuit is from a...