We found this circuit in a Popular Electronics from the 90s. Its purpose is to monitor a power line. The circuit uses optical couplers of the time.
Found in documentation from the 90s, this circuit can employ other comparators in the series such as...
This circuit was found in a PE Hobbyst Handbook from 1992. The second oscillator is a VFO. The...
This motor control using transistors was found in a recent English publication. The circuit is for...