Found in a 1967 RCA documentation, this AC power grid contactor can be fitted with modern equivalent components. The SCR and the diodes must be according to the load current.
This circuit is like the previous one except that it can be triggered electronically. The circuit is...
Found in 90s Radio Electronics, this audio indicator makes use of an integrated circuit that is...
Found in the October 1992 Radio Electronics magazine, this oscillator is controlled by switch S1....