This variable filter circuit was found in July 1975 Radio Electronics magazine. The circuit uses 3 general purpose op-amps like the 741 and must use a symmetrical source.
This simple PWM circuit was found in the March 1991 issue of Radio Electronics magazine. The...
Found in documentation from the 1960s, this circuit uses general purpose transistors that can...
At dusk this circuit triggers a relay switching lamps. The circuit can be powered from 6 to 12 V...