This circuit was found in 1960s Radio Electronics. The circuit uses components from that time. The triac is according to the controlled load. The sensor is a common LDR.
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...