Using a common crystal diode and a 741, this circuit can be used to detect microwaves. The circuit is from old documentation and the switch selects the gains.
This circuit provides two slightly different audio signal outputs from a monophonic audio signal, so...
This detector is from the 1990 Motorola Dataar Databook, but can be adapted to work with more...
This traditional configuration of astable was found in a 1965 documentation. Transistors can be...