Desk lamp dimming soft switch circuit

It uses a bidirectional thyristor dimming circuit and a photoresistor instead of a potentiometer , so it has a long service life ( potentiometers are relatively prone to problems).     Just after the power is turned on, since the photoresistor RG has not yet been exposed to light, its resistance value is very large, so the conduction angle obtained by the bidirectional thyristor V is very small, and the brightness of the lamp EL is very dim. As the RG is exposed to more light, the resistance gradually becomes smaller, and the lamp becomes brighter and brighter until it reaches the predetermined brightness, thus avoiding the impact of large current on the lamp when the light is turned on, and greatly extending the life of the lamp. Dimming can be achieved by adjusting the light shield in front of the photoresistor . Photoresistor RG can be selected from MG41-MG45 types.