Touch-type electric fan eight-speed speed regulation circuit

The circuit is shown in Figure 3-7. Just touch the sensor piece (conductive piece) with your hand. Eight gears of speed adjustment can be achieved.
    The timing pulse oscillator is composed of NAND gates 1 and 2 in the CC4011 integrated circuit Ai. When the conductive sheet M is touched by hand
, Ai starts to vibrate and sends counting pulses to the CC4017~ forward counting/pulse distributor Az. The output terminals Yl~Y9 of A2 output high levels in sequence, and pass through the resistors R~
of different resistances . ~Ria reduces the voltage and sends it to the photocoupler B, which then controls the conduction angle of the triac V to achieve eight-speed speed regulation. Resistor R6 level is 62kC1, R7~R1a need to be determined by actual debugging, so that the voltage difference between two adjacent gears (voltage at both ends of the motor) is 25~30V.