Found in old American documentation, this circuit that can be used as a shield, activates two relays and a neon lamp with different voltages.
This circuit is from a 1980s Motorola documentation. The circuit can be made with modern...
This well-known circuit triggers a relay when light striking the phototransistor is cut off. The...
This circuit generates a pulsed tone whose frequency depends on C2 and whose flashing depends on...