Found in the September 1982 issue of Radio Electronics magazine, this circuit triggers a relay intermittently. Triggering is done by a reed switch, but other types of sensors can be used.
Obtained from an English publication, this circuit actually needs a current limiting resistor,...
This circuit has its gain determined by the control DC voltage. The circuit is from a Radio...
This oscillator is a 1950s application of one of the first types of commercial transistors, the...