Here is a simple, yet useful circuit of an Arduino 4-digit 7-segment LED display unit. The module used here is ... D13 of the Arduino is reserved for the decimal point segment. The 10K potentiometer ...

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 Board, a small BC547 transistor and a potentiometer ... as a voltage divider ...

Instead of the relative horror of driving 40 LEDs with a single Arduino ... To actually power and control the entire circuit, [Martyn] used an Arduino loaded up with a program based LedControl ...