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.
This circuit uses three inverters to generate a rectangular signal whose frequency depends on R1...
This control circuit or reversible contactor was found in a 1967 General Electric manual. The...
This circuit counts from 1 to 10 or 0 to 9 using as indicators common LEDs. The circuit can be...