The purpose of this circuit is to improve a trigger circuit using a zener diode. The circuit was found in an American documentation from 1964. It can be improved using equivalent modern components.
The circuit in the figure is based on an LM101A; diodes can be replaced with equivalents. The...
This circuit, with magnetic sensor, uses an operational amplifier of the time. The circuit is from...
Found in a 90s Popular Electronics, this circuit checks if a remote-control transmitter is...