Ventilation fan infrared remote control switch circuit

Shown is an infrared remote control switch circuit for a power-changing air fan . The circuit is mainly composed of a power supply circuit, an infrared remote control
receiver IC1 and a control circuit. In this circuit, the power supply circuit is mainly composed of
    power switch S, capacitor cl, resistor Rl, bridge rectifier stack VD1-VD4, Zener diode vs and filter capacitor C2; IC1 is an infrared remote control receiver; the control circuit mainly It is composed of transistor VT, resistor R4, relay K and diode VD5.     When the power switch S is turned on, the AC 220 V will be stepped down, rectified, stabilized, and filtered to output a DC voltage of about 5v to provide working voltage for other components in the circuit. When the remote control is pressed to control the operation of the power-changing air fan, the infrared connector IC1 receives the infrared signal from the remote control, and its output terminal @ pin outputs a low level, and then outputs a high level through IC2 and is inverted by IC3 Make the ③ pin of IC4 change to low level, and then after processing by IC4, its @ pin outputs a high level, triggering the transistor VT to conduct, the relay K to pull in, its normally open contact Kl to pull in, and the load is turned on The power supply starts working.