Electric fan natural wind power supply control circuit

Circuit working principle: CC7555 circuit and peripheral components form a square wave pulse oscillator with adjustable duty cycle
. Use VD, VD4 to separate the charge and discharge circuit of capacitor C, and then
adjust the potentiometer RP to change the duty cycle of the pulse oscillator. empty ratio. When using,
insert the power plug of the electric fan into the socket xs. S is the function selection switch. When "S" is placed in the A-*B position
, it is the natural wind function. At this time, the 220 V AC power supply is step-down by C,
rectified by VD, VD2, filtered by C2, and stabilized by ZD, and a 9 V DC power is obtained to supply the
working The CC7555 circuit starts to oscillate, and a square wave pulse is output from pin 3. When pin 3 outputs
a high level, the transistor VT is turned on, and the control board of the triac VS gets the trigger
voltage and turns on. The AC power supply of the socket (xs) is connected, and the electric fan is powered to run.
At the same time light-emitting diode LED emits red light. Light indicates that socket xs gets 220 V AC power.
When pin 3 of the CC7555 circuit changes from high level to low level, the transistor VT is cut off,
the triac VS control pole loses the trigger voltage and is cut off, cutting off the AC power supply of the xs socket
, and the electric fan stops running.