you create your OR functionality with diodes - use two diodes (or as many inputs as you need) such as the 1N4001 for your inputs. Tie the cathodes together and attach that to the relay coil. Apply "logic high" (whatever voltage your relays operate at) to either (or any) diode anode and the relay will turn on. The relay can be the next stage and does not have to be there to implement the OR. best regards, Steve Thatcher Question: Wouldn't it be easier to implement an OR gate with no relays at all (just two wires joining together)? Or would you need to use the relays to keep the output voltage/amperage regulated? Cheers, Ade.