High-power AC voltage regulator (verified, but not perfect)

Please do not order the BOM directly! Some components only use their packages; please refer to the schematic diagram for specific parameters!
 
Principle:
The LM358 operational amplifier generates a low-frequency square wave oscillation with a continuously adjustable duty cycle of 0-100%, controlling the conduction and cutoff of the thyristor. When it is not necessary to reduce the power of the appliance, simply turn the knob with the switch all the way to close the relay, short-circuiting the thyristor.
 
Function:
Insert the rice cooker cord into the triangular connector, insert the appliance into the 3-pin 220V output interface, and turn the knob to adjust the appliance's power. A row of LEDs provides a semi-quantitative indication of the current power. When the last LED lights up, it indicates that the relay is engaged, and the appliance will be directly connected to the 220V AC mains without any other circuitry.
 
Imperfections:
1. The 24V to 5V conversion section in this circuit cannot work stably. It is recommended to use the most common LM2596 module from Taobao to replace this part of the circuit. The 3D casing has a reserved position for this module, located on the left side of the circuit board, requiring a jumper wire connection.
2. The thyristor has significant power dissipation and requires fan cooling. The 3D casing has pre-drilled mounting positions and screw holes for the fan, and the PCB also has corresponding fan power supply headers. Please use a 2.5cm*2.5cm 5V small fan.
 
Precautions:
1. The input and output of this circuit are not isolated; please pay attention to electrical safety.
2. I used this circuit to power an old-fashioned 1500W electric hot pot, and it has been working for over a year without any problems. However, I haven't tried it with higher-power appliances.