This circuit is from an American manual from 1975. The transistors are types of the time, but equivalents can be used, as well as the relay that can be according to the supply voltage.
This simple shield for microcontrollers and TTL digital circuits was found in documentation from...
In the figure we have the transmitter and the receiver for an optical audio link via infrared. The...
This bistable or flip-flop is triggered by a negative pulse applied to the collector of the...