This circuit was found in the February 1970 issue of Radio Electronics magazine. The integrated circuit is a type of the time. It consists of a high-gain differential amplifier.
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...