Automatic Light Intensity Control System

This paper demonstrates an easy and energy efficient automatic light intensity control system which does not need much maintenance. The cost of the system is 125 rupees(Rs.). Earlier the high intensity incandescent bulbs were used. The disadvantage of these high intensity incandescent bulbs is that the intensity cannot be varied according to the requirement. To overcome this limitation “Automatic Light Intensity Control System” is developed. To overcome the limitations specified above, it makes use of LDR(Light Dependent Resistor) whose resistance varies according to the brightness of the surrounding environment and simultaneously its intensity can be varied and controlled automatically. The system also comprises of a TRIAC, DIAC, Capacitor, Resistor and connecting wires. So when external light is low, the light intensity is high and as external light increases the intensity of Incandescent Bulbs decreases accordingly to save power. In this the sensor which will be used is LDR(Light Dependent Resistor).The resistance of the LDR (Light Dependent Resistor) varies according to the brightness in the surrounding environment .It decreases when its dark outside and increases when its bright outside or it varies inversely with respect to the brightness of the surrounding environment or the light falling on its surface. By using the LDR we can control the intensity of the incandescent bulbs. The resistance of the LDR varies according to the brightness in the surrounding environment. Triac had been used here to control the current through the circuit. Diac had been here to trigger the Triac(gate triggering) a protective resistance had also been used here.