Found in a 90s Popular Electronics, this circuit checks if a remote-control transmitter is emitting signals. The sensor is a general-purpose type found in many electronic devices.
This simple 10-position roulette circuit with the 4017 found a 1987 documentation. The circuit can...
With this circuit it is possible to obtain an AND gate with large fan-in, using an operational...
The figure shows how to increase the output current to about 50 mA of an operational amplifier. The...