This is a PWM video tutorial. This video talks about the PWM and how to use it. The PWM can be used  to dim the LEDs or control DC motor speed. By changing the width of the pulse, we change the average voltage. Usually, to generate the PWM we use the function generator. However we can build a simple PWM generator using 555 IC. The additional components for the circuit are resistor, potentiometer, NPN transistor, diode and Capacitors. The examples of the use of PWM are dimming the LCD of the laptop and speed control on RC car. Here is the video: