Indoor fan control circuit for air conditioner

Single chip microcomputer STM32L151CCU6

Probe domestic switch needle KG300B head diameter 3.0 normally closed switch needle total length is 5

Adjustable capacitor Murata genuine original

TZC3Z030A110R00 MURATA Murata adjustable capacitor original spot

The indoor fan control circuit for air conditioning is shown in the figure.
The specific control method of the indoor fan wind speed is as follows: first, the zero-crossing detection circuit detects the zero-crossing point of the AC220V, and generates a zero-crossing interrupt; then, in the interrupt processing subroutine, the timer timing function is turned on. The on-time of the AC220V in each half cycle can be controlled by the change of the timing length of the timer, thereby controlling the power and speed of the indoor fan.
In the figure, the 3 pin of U1 is the trigger pin and is driven by the triode. U1 is an optocoupler thyristor that is used to control the on-time of the AC220V to adjust the wind speed of the inner fan. AC220V is input from pin 11 and pin 13 is output. The specific on-time is controlled by the trigger of the firing angle.