We found this circuit in the magazine Eletcronics Now of July 1994. The power supply is according to the relay and the transistor can be any general purpose one.
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...