This two-transistor circuit was found in the September 1971 issue of Radio Electronics magazine. The sensor is an NTC and sensitivity adjustment is via R1.
This traditional configuration is from a 1976 publication, showing that nothing has changed since...
This circuit is from a Radio Electronics from February 1971. The SCR is load controlled and the...
This timer triggers high-powered loads powered by the power grid. Times are given by C1 and the...