Found in an American publication of 1968, this circuit makes use of a pilot light of the time. It can be replaced with LED with appropriate series resistor. Transistors may be modern equivalents.
We found this circuit in a 1967 American documentation. The diodes are general-purpose and the...
This circuit uses a pressure switch to turn a relay on or off. The supply must be 6 or 12 V...
The selected circuit was found in the Texas Instruments optoelectronics manual. RC and C1...