This circuit was found in a 1971s English magazine. We can still assemble it using BC548 transistor. The other components are common. The supply voltage of 6 or 12 V depends only on the relay.
I found this circuit in an English magazine from July 1982. The circuit is still viable because all...
This 75 W power supply was found in American documentation from the 1980s. Transistors can be...
This simple transistor amplifier is from 1982 documentation. The output transistor must be mounted on...