The circuit controls both low voltage (from 24VAC to 240VAC at 5.5A) AC motors and mains voltage (110VAC or 220VAC) loads.
R1: 4.7K resistor
R2: 3.3K resistor
R3: 680 ohm resistor
R4, R5: 22K resistors
R6: 1.5K resistor
R7: 47K (50Hz), 10K (60Hz)
R8: 100K resistor
R9: 100 ohm resistor
R10: 120 ohm resistor
R11: 68 ohm resistor
R12: 1K resistor
R13: 27 ohm resistor
R14: 390K resistor
RV1, RV2: 100K trim potentiometers
C1: 470uF electrolytic capacitor
C2: 1uF electrolytic capacitor
C3: 100nF capacitor
C5: 47nF capacitor
C6: 100nF/400V capacitor
C7: 47nF/400V capacitor
D1, D2, D7: 1N4007 diodes
D3-D6: 1N4148 diodes
T1-T3: BC547B transistors
T4: BC517 transistor
TRI1: BT137F-600 Triac
F1: 250mA slow fuse
F2: 5A slow fuse
L1: 50uH/1kHz coil
Trafo1: 2x6V/1x0.3A
Heatsink for the triac
terminal blocks (VAC, load and mains)
J1, J2 mains voltage jumpers