Touch dimming circuits are gradually being used in indoor lighting. Through IC integration, peripheral circuits are simple and there are not many electronic components. In the circuit diagram below, there are three levels of dimming, which are divided into strong, medium and weak. At the beginning, when the power switch is 'on', the light is 'off'. Now, when you touch the trackpad, the lights dim. At the second touch, the lamp provides medium light. With the third touch above, the light is fully powered.        

IC is a very sensitive device, using a long wire to connect the IC to the touch sensor. The touchpad can also use a simple copper plate of 1 cm x 1 cm or simple lead ends. The orientation of the touch panel is connected to the touch detectors, which are coupled in series through 820PF, 2kV capacitors C1, C2, and C3. (Related reading: PPTC protection application in electronic shoe cabinet)        

The touch signal of the internal IC TT6061A is connected to the counter/decoder through a resistor and through a frequency generator, the counter/decoder is connected to the clock input terminal CK and the horizontal frequency signal is obtained through R4 at pin 2 of the IC TT6061A.        

At the zero-crossing point, the thyristor (BT136) triggers to drive a 200W bulb directly from the 6.8V power supply through resistors R1 and R3, diode D3, capacitor C4, and Zener diode IC's power input terminal 3. (Recommended reading: Application of self-recovery fuse in washing machine protection)       

 Capacitors C1, C2, and C3 are connected between the touch input terminal 4 and the touchpad touchpad, so do not change these capacitances, use a capacitor's capacitance or a lower voltage level. Circuit power potential.       

 Obviously, this is a high risk when the power of the touch circuit is 'on'. To solve this problem, using PPTC as a protection is the most ideal and necessary solution.