This circuit, found in a 1964 US documentation, consists of a selective amplifier that lets only 10 Hz pass around a 400 Hz center frequency with the indicated components.
This circuit trips when a negative pulse is applied to its input or when the voltage drops below a...
This is an old 1988 circuit consisting of a timer or time control for exposing silk-screen arrays. The...
This circuit was taken from an old American documentation. It can be built with modern op amps. The...