This source for 50 W amplifiers per channel was found in 1967 Delco documentation. Transistors are from that time, difficult to obtain today.
This small regulator with transistors can supply 75 mA currents for charging NiCad rechargeable batteries....
This circuit was found in 80's Popular Electronics. The circuit uses an infrared-sensitive phototransistor...
This circuit was originally published in a 1966 book from Spain. The circuit uses a...