Pulse width Modulation

Pulse width Modulation is the important concept in the field of analog electronics. It has various applications and it is not limited to one particular field. Let it be Communication systems or Power electronics or Microcontrollers.
Pulse width modulation is used  everywhere.So for a electronics/electrical engineer  it is very  essential to understand the concept. 

 Pulse width modulation , as the name suggests, is a technique in which the output pulse width is varied depending on a input signal. 
let's go ahead and study simple pulse width modulation

Circuit 

The circuit consists of triangular wave generator and a comparator.The inputs to the comparator are 

1)triangular wave

2) constant Dc voltage

Refer this tutorial for generation of triangular wave : TRIANGUAR WAVE

The comparator  is nothing about Opamp without feedback. So without feedback ,Opamp output will be Positive or negative saturation depending on the value of voltages at Inverting and Non inverting terminals. 

Two cases 

1) IF noninverting terminal voltage is greater than inverting terminal, output will be in positive saturation

2)IF noninverting terminal voltage is less than inverting terminal, output will be in negative saturation

So depending on the value of DC voltage, the Pulse width of the  square wave is varied. Hence the name Pulse width modulation.