Found in a 1969 Electronics World, this circuit generates low frequency signals with two repetition bands. Transistors support modern equivalents.
With a touch of the sensor, the SCR fires and keeps the lamp on. To deactivate the circuit, it is...
This small FM transmitter has a sensitive modulating stage and is therefore suitable for listening...
The sensor diode used in this circuit is the common type of germanium. Experiments may be made...