If you would like to learn the basics of electronics and soldering electronic components together to make more complicated projects. A good starting point is the Arduino Make Your UNO Kit, providing ...
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 ...