Found in an American documentation from the 90s, this circuit has a configuration that has been extensively explored in other articles on this site. The FET can be the MPF102 or equivalent.
The circuit presented is based on a mechanical tuning fork. The circuit is suggested by National...
In this circuit of Texas Instruments an incandescent lamp is used as a light source, and lenses are...
One touch of the push button S1 and the circuit LEDs shown in the figure start to flash rapidly. The...