In this quick Arduino tutorial I will explain how you can control a relay using the Arduino Board, one 1K and one 10K resistors, 1 BC547 transistor, one 6V or 12V relay, one 1N4007 diode and a 12V fan ...

In first the prototype board shied hadn’t had any semiconductors on it, but he had to add them, to get rid of some additional old boards, so he could only keep the relay cards and the two mains ...