Simple and practical air conditioning indoor fan control circuit diagram

This article will share a simple and practical indoor fan control circuit diagram for household air conditioners. As shown in the figure below, U1 in the figure is an optocoupler thyristor, which is used to control the conduction time of AC220V to adjust the wind speed of the internal fan. Pin 3 of U1 is the trigger pin and is driven by a triode. AC220V is input from pin 11 and output from pin 13. The specific conduction time is controlled by the trigger angle.

Indoor fan wind speed control method: First, the zero-crossing detection circuit detects the zero-crossing point of AC220V and generates a zero-crossing interrupt; then, in the interrupt processing subroutine, turn on the timing function of the Timer, such as timing 4ms, and the CPU generates a trigger after 4ms The pulse, driven by the transistor, is input from pin 3 of U1, triggering the internal circuit of U1, thereby turning on pins 11 and 13 of U1, and AC220V supplies power to the indoor fan. In this way, the conduction time of AC220V in each half cycle can be controlled by changing the timing length of the timer, thereby controlling the power and speed of the indoor fan.