We found this circuit in the August 1994 issue of Electronics Now magazine. The circuit is based on the now uncommon CMOS 4046. The frequency range is given by C1.
According to its author, this device indicates the amount of force applied to the sensors. The...
This is a circuit for testing small lamps and LEDs. The lamps that can be tested are the ones...
We found this circuit in an American documentation from the 60s. The circuit can be made with...