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.
The circuit shown here uses a 4047 to produce three signals whose frequencies are determined by C...
We found this circuit in an old English publication. The resistor not indicated can be 2k2 and the...
This circuit was found in documentation from the 1980s. The integrated circuit used is uncommon today...