This circuit was obtained from a 90s Radio Electronics. The integrated circuit used HAA11508 is not a common component today.
This dimmer for incandescent lamps was obtained from an American 1990s documentation. The circuit...
This headphone amplifier has good gain and high input impedance. The circuit is from Electronics Now and...
This circuit is from an English publication from 1981. It can still be assembled with transistors BC548...