This circuit consists of an electrostatic sensor that can check if a cable is energized by simply approaching it. The circuit is from an Electronics Now from December 1998.
We found this circuit in a Motorola documentation from 1978. The circuit is based on the LM324...
This crystal-controlled oscillator can generate signals up to a few dozen megahertz. We found it...
We found this circuit in the October 1987 Radio Electronics magazine. The circuit uses an...