Photoelectric remote control power switch circuit diagram

The working principle is shown in Figure 1. It is a light-controlled power- off remote control device that can be triggered by the light of the electric wire. The circuit consists of two parts: one part is the light control circuit; the other part is the controlled circuit. The light control part is composed of phototransistor VT1 and potentiometer RP phase transistor VT2. The controlled part consists of transistor VT3 and relay KM. When the key switch SB is pressed, a DC voltage of ten l 2V is obtained at both ends of the Zener diode vD5. The light-emitting diode VI)6 shows the operation. Because vT1 is not illuminated by the flashlight, the space between c? of vTl is a reverse bias resistor, vT2 is cut off, the collector of vT2 is at high potential, VT3 is saturated and conductive, and the relay KM operates. Contacts KM-1tKM-2 are closed, and socket XS has a unique 220V AC power supply. When the electric light hits VTl, there is a reverse bias resistor between CE of VTl, and the resistance becomes smaller so that vT2 is turned on, the collector of vT2 is at low potential, vT3 is cut off, the relay KM will be released, and the contacts KM-1 and KM-2 Disconnected, the power supply on xs is cut off. Resistor Rl provides a bleed current loop for capacitor C1. vD7 is the protection diode.