Operating in class AB1, this high-fidelity amplifier was found in the 1961 RCA tube manual. The circuit has high input impedance and good gain.
This 1985 circuit takes advantage of an old cassette recorder to answer and record phone calls,...
This circuit is from 1990 documentation. It can be implemented with BC548 transistors instead of...
We found this 50 kHz 25 MHz crystal tester in a 1978 QST magazine. The FET can be the BF245 and...