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.
Using a capacitor as a sensor, this circuit was found in the 1989 Radio Electronics Experimenter magazine....
Using bipolar, FETs and unijunction this long-lasting timer can reach 10 hours with good quality...
This circuit is found in an American documentation from the 80's. The circuit measures the power of...