220v Light Bulb Dimming Circuit

INTRODUCTION

A light bulb is a device that illuminates a place. It makes light by heating a metal filament wire to a high temperature until it glows. This is done by supplying electrical current to the feed-through terminals or wires embedded in the glass.

Pulse-width modulation (PWM) is a commonly used technique for controlling power to inertial electrical devices, made practical by modern electronic power switches. It is a way of digitally encoding analog signal levels. The voltage or current source is supplied to the analog load by means of a repeating series of on and off pulses. The on-time is the time during which the DC supply is applied to the load, and the off-time is the period during which the supply is switched off. Given a sufficient bandwidth, any analog value can be encoded with PWM.

With those ideas above, the objective of the project is to be able to apply PWM to a 220v light bulb. This means that the system will be able to control the light intensity of the light bulb by altering the amount of voltage being fed to the bulb at a certain period with the use of the PWM module of the PIC16F877 microcontroller through varying the potentiometer.