Dc motor are mostly used in industries so we used to control the speed of the motor by using PWM. In this paper, to control the speed of DC motor using Pulse Width Modulation (PWM) method. Microcontroller AT89S52 is used to generate PWM. L293D IC is used to drive the motor which is made up of two H-Bridge. 555 IC is used with opto coupler to sense the speed of DC motor. Rectifier circuit is used for power supply to circuit and motor. This paper shows that precise and accurate control of small DC motors without using costly components.

Keywords : PWM , Microcontroller, DC Motor.