Intelligent monitor for class room illuminance

The utility model relates to an intelligent monitor for class room illuminance, which controls the electric light by the light on the ground of the request of the illuminance. Three electrodes of a bidirectional controlled silicon are arranged on a circuit board in a plastic box. The control electrode is welded with one end of a bidirectional trigger diode. The other electrode is welded with ends of a transformer input coil and a fixed resistance. The third electrode is welded with the ends of two photoconductive resistances, a fixed capacitor, an electric light connection wire and a 220V power supply wire. The other ends of the bidirectional trigger diode and the fixed capacitor are welded with one end of a variable resistance. The other ends of the fixed resistance, the variable resistance, the photoconductive resistances RG1 and RG2, the electric light connection wire, the 220V power supply wire and the transformer input coil are respectively welded with contacts 1, 2, 3, 4, 5 of a relay. The regulated power supply of the relay operation is composed of a rectifying tube, the transformer and an electrolytic capacitor. The circuit is provided with the two photoconductive resistances which have different parameters and can be adjusted by accepting the quantity of light. The two photoconductive resistances respectively monitor the illuminance of the electric light opened and closed, eliminates the interference of the light against the light controlling and automatically open or close the electric light on the ground of the set illuninance.