This circuit, with 1 A output, was found in a 1975 documentation. The transistors admit equivalents and the transformer has windings according to the voltages being worked.
This circuit generates the busy tone of ordinary telephones. The transistors can be the BC548 and...
This small 1 W amplifier uses a Motorola integrated circuit from the 1970s. The integrated circuit...
This is a configuration widely used for oscillators with crystal from 1 to 20 MHz typically. The...