GELCO auto photo is a power saver for large external lighting installation where switching off the lights is dependent on natural day light & where even manual control becomes physically tedious due to the large distance involved. It switches on the lights at dusk and switches off the lights at dawn. Airport runway lights, railway station lights, advertisement neon sign displays, stockyards, housing colonies etc. It employs a light sensor exposed to the natural light. It generates an electrical pulse, which activates electro magnetic relay which cut-off the electric current. A potentiometer is provided for the final setting. The unit is available in single phase upto 25 amps & in three phase upto 200 amps. It is available in two models viz. Indoor model & outdoor model. Basic unit measures 170 x 165 x 85 mm b & weighs 1.5 kg for 25 amps. It is easy to install.