Found in a 90s American documentation, this circuit uses an integrated from the time that is difficult to obtain today. The sensor is a common photodiode.
This circuit is from the 1993 Motorola Linear Interface Circuits. The source does not have to be...
This range is normally used in marine communications as indicated in the 1989 documentation. The...
This shield circuit is from a 1968s Motorola documentation. The relay is according to the supply...