This flip-flop controlled by an LDR-type photocell was found in Radio Electroinics magazine from June 1959. Note that it can be powered from the mains and directly controls a sensitive relay.
This circuit uses unijunction transistors and drives a small speaker through an output...
This interesting game was found in a 1987 publication, but it is very simple and can be easily...
This circuit uses a thermistor or NTC as a temperature sensor and provides the indication on an...