Light control relay control lamp

220V AC by the step-down transformer T, a diode VDI-VD4 bridge rectifier and filter capacitor CI, output of about 12V DC voltage for the entire circuit use. Light control circu

it consists of VTI, RG, Rl and the like RP components constitute the daytime sensitive electrical resistor RG affected by light exposure exhibits low resistance, the transistor VT conduction, the collector output low, the relay control transistor VT2 in the off state, relays loss of power does not act, the normally open contacts open, which controls the lighting does not work. Late Rooms, photoresistor RG light exposure and showed a high resistance, VT1 base potential to reduce the cut-off, the collector output high power level, VT2 off on the original state into the conduction state, the relay K is energized its normally open contact closure, can be switched according to the power supply so that the lamp lighting lights up. RP s resistance to change can change the size of the transistor VT1 base potential, it can be used to adjust the sensitivity of the light control circuit.

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