This two-digit (up to 99) circuit divides a signal by values programmed by the BCD switches. The circuit comes from a Radio Electronics from February 1989.
Found in a 90s Popular Electronics, this touch switch uses a single sensor. PLLs are common today....
We found this circuit in an old documentation from 1979. It is a logic level tester that is...
This ultrasonic insect repellent was found in American documentation from the 1980s. The...