Found in a Hands-On Electronics from the 90s, this circuit produces the dial tones of an old telephone. The integrated circuit used is uncommon today.
The relay of this circuit closes when the position set in P2 is reached by the sensor...
In this circuit the output voltage is given by xx. The L series circuits are for a maximum current of...
This circuit consists of an electrostatic sensor that can check if a cable is energized by simply...