 INTRODUCTION

Pulse width modulation (PWM) or pulse-duration modulation (PDM) is a technique for getting analog results with digital means by PWM we will generate a defined clock signal.

Digital control is used to create a square wave, a signal switched between on and off.

This ON and OFF pattern is difference between 5V to 0V.

IDENTIFICATION OF PWM PINS ON ARDUINO UNO

In arduino uno the pins which contain this (~) are pwm pins like-11,10,9,6,5 and 3

CIRCUIT DIAGRAM

To check or get PWM signal we will use led as load

DIGITAL SIGNALS

Here 1 is 5v or 3.3v and 0 is 0v

DUTY CYCLE

In the pulse wave there are logic 1 , logic 0 which defines the on and off period of a wave form . If on period is equal to the off period the wave formed is square wave and THE RATIO OF POSITIVE CYCLE AGAINST THE TOTAL DURATION IS CALLED DUTY CYCLE

For example- The duty cycle varies. If it is pulsed ON for 0.05 seconds in a 0.1-second cycle, the fuel injector duty cycle equals 50%. If it pulsed ON for 0.09 seconds of that same 0.1-second cycle, the fuel injector duty cycle equals 90%.

CODE

int led ;

led = 11;

void setup() {

pinMode(led,OUTPUT);

}

void loop() {

int i;

for(i=0; i<=225; i++)

{

analogWrite(led,i);

delay(500);

}

for(i=225; i>=0; i–)

{

analogWrite(led,i);

delay(500);

}

}

VIDEO TUTORIAL