This is an easy tutorial showing how you can control the brightness of an LED or adjust the speed of a DC fan using Arduino ... transistor and a potentiometer. In my example the whole circuitry is ...

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 ...

To the human eye, it looks like multiple LED’s are lit up simultaneously. [Alex] planned to use an Arduino to control ... the signals through a set of PNP transistors to flip the logic.

If you’re looking for a more entry-level Arduino LED cube this 4x4x4 project is ... below – bottom right – shown passing through NPN transistors). The Arduino Mega 2560 R3 is positioned ...