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 ...

This part number (and ofcourse the LED type) is not very critical. If you want to use a bi-polar transistor, don’t forget to add a resistor (~1KΩ ) between Arduino D10 and the base terminal of the ...

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.

[Fileark] built and ESC using an Arduino and has a couple of posts explaining the concept and demonstrating how it works. His test circuit uses six 2N2222 transistors to protect the Arduino from ...