This amplifier was found in a tube equipment manual from 1947. The high-fidelity circuit has pentode tubes at the output and a source with transformer.
This two-transistor constant current source is from a 1968 documentation. Modern equivalent...
This circuit was obtained in a 1977 technical documentation. The PUT admits equivalent and the...
We found this circuit in a 1997 documentation. Its purpose is to turn a load on or off using...