This 4-channel mixer amplifier was found in an American publication from 1947. The circuit uses counterphase output tubes and a transformer power source.
In this circuit the relay triggers on when light falls onto the sensor, a common LDR. Power supply...
This circuit emits a warning sound when night falls. The circuit is from a Hands On Electronics from...
This circuit can measure capacitances in various ranges using a common analog indicator. The...