This shield circuit is from an American documentation from 1969. The components can be modified according to the relay and power, and the coupler can be of a modern type.
This circuit is from a technical documentation from Texas Instruments from 1978. In it we have the...
We found this circuit in an old documentation, but it is still current, being able to feed sets of...
This circuit, found in a 1995 documentation, makes the relay bistable control from pulses of light...