Found in an American documentation from 1968, this circuit senses the temperature through an infrared sensor of the time. The indicator is analog.
This simple receiver for listening on a crystal phone tunes the range of medium waves. The circuit...
The figure shows a circuit that shows how to control an optodiac to trigger a triac from the...
This configuration was found in a 1976 documentation. Note the use of pin 4 input for reset. The...