This very low current circuit was found in the April 1995 Electronics Now magazine. The frequency should be chosen for maximum efficiency according to the small transformer used.
This circuit, from the 90's, is intended for operation with vinyl record players of the time, as...
Using a zener diode it is possible to change the linearity of the scale of an analog instrument by...
Found in American documentation from the 1980s, this circuit prolongs the ringing of a doorbell or chime...