Found in a 90's EDN, this circuit can be used as a shield. The components depend on the MOSFETs and the load that must be controlled. The logic is TTL.
We found this circuit in a 1968 Electronics World. The potentiometer should be set to trigger the SCR...
We found this circuit in a documentation from the 90s. It lets frequencies around 1 kHz pass,...
This wired intercom circuit was found in a March 1965 Radio Electronics. The circuit uses two...