Use CD4011 and CD4017 to make a touch-type five-speed dimmer

The touch-type five-speed dimmer circuit made with CD4011 and CD4017 is shown in Figure 3-21. The left part of the dotted line in the figure is the ordinary lighting circuit, and the right part is the five-speed dimmer.     VDI-VD4 and vs form the main circuit of the dimmer . The brightness, darkness and extinguishing of the bulb H all depend on the conduction status of the thyristor vs. VD14 and c5 form a simple voltage stabilizing circuit, so that both ends of c5 output a DC voltage of about 12V for power consumption of integrated circuits Al and A2.     Al is a 4-2 NAND gate. Its two NAND gates on pins 8 to 13 form an ultra-low frequency oscillator. Whether it oscillates or not depends on the potential of pin 13. Usually, pin 13 is at low level because R2 is grounded, and the oscillator stops vibrating. When the human hand touches the electrode sheet Ml , the human body induced alternating current is added to the 13th pin of Al through R1, making pin 13 high level, the oscillator starts to oscillate, and the oscillation pulse is sent from the output of pin 10 to the ten-count system, and the timing is decoded The 14th pin of device A2, i.e. the CP side, is used for counting. Therefore, QO~Q8 of A2 appear high level in sequence. When Q8 is high level, this high level is added to the Cr terminal, i.e. pin 15, through VD13 to clear A2, completing a cycle. When Q2~Q7 appear high level one after another, it charges . When the voltage across C3 rises to 1/2 Vr)o, the two NAND gates of pins 1 to 6 of Al flip. Pin 3 outputs high level, and the thyristor VS is turned on through R5, and the light turns on. When vs is opened. The charge stored in C3 is discharged to vs through VD6. Pin 3 of Al outputs a low level, and vs is turned off. C3 starts filling again, and the cycle starts again. Since the resistors R8~R12 connected to the output terminals of Q2~Q7 have different resistance values ​​(?20k 0~82k Q), the time required for the C3 voltage to charge to 1,2 VDD is different, thus changing the conduction angle of vs, so it can Get five different levels of brightness.     M2 is the "off" electrode piece. When the lamp is at any brightness, just touch M2 with your hand. The alternating current induced by the human body is added to the Cr terminal of A2 through R14, so that A2 is cleared and reset, and the lamp is turned off. The lamp is in the off state. and the brightest state respectively occupy two output terminals, namely QO, Ql and Q6, Q7, so the CP terminal, i.e. pin 14, needs to input 2 count pulses to change this state, which is beneficial to improving the anti-interference performance. Capacitor C2 It can absorb interference pulses and eliminate false triggering of VS caused by voltage fluctuations in the power grid.