Relay Q&A Forum › Relay 0 Vote Up Vote Down Joel Jacob asked 6 years ago How do we check if a relay is faulty? Does a 5V relay work on 4.5V? Thanks in advance 1 Answers 0 Vote Up Vote Down Rui Santos Staff answered 6 years ago Hello Joel, a 5V relay module should be powered with 5V to work properly. However, if you send a HIGH signal at 4.5V to the INPUT it should turn it on/off…