Still needs some improvement, such as:
Fuse is placed right after diode bridge.
Zero crossing detected.
Test point voltage at input and gate control.
Thermal feedback at heatsink.
Zener 1N4742A = 12V, 33 = 5.1V.
Relay enable for input power supply and check mode initially.
Cannot use for motor, only use resistor load such as bulb and resistor coil.
Fan enhancing for heatsink.