This circuit was suggested by Texas Instruments in a 1980s documentation. The transistor must be equipped with a heat sink. The transformer has 10 A secondary current.
This headphone amplifier has good gain and high input impedance. The circuit is from Electronics Now and...
Found in an 80's Elektor, this circuit can use any equivalent optical coupler. The buzzer is of the...
Incandescent lamps and heaters can be controlled by a low power switch using this circuit. The...