This old configuration of an audio amplifier has a push-pull two-transistor output stage. Output power is low and the critical components are the transformers. The circuit was found in an 1958’s publication.
This simple 555 biofeedback circuit was found in the December 1983 issue of Radio Electronics...
Found in a 1969 EDN, this high current circuit, not indicated in the documentation, uses...
This tester for common unijunction transistors is nothing more than a low frequency oscillator...