Found in the July 1994 Electronics Now magazine, this circuit drives a relay up to 12 V depending on the power supply. The transistor can be general purpose.
This circuit uses a 741 operational amplifier that must be powered by a symmetrical source of 6 to...
This oscillator generates a 1 kHz signal, using an old germanium PNP transistor. The circuit was...
This circuit was obtained from a Radio Electronics issue from January 1989. The indicator is a...