Touch switch is an emerging product with the development and progress of science and technology. Generally, it refers to a wall switch designed by applying the principle of touch sensing chip, which is a replacement product of traditional mechanical button-type wall switch. The touch switch that can realize more intelligent and more convenient operation has the incomparable advantages of traditional switches, and is a very popular decorative switch for household products. Touch switches are classified into resistive touch switches and capacitive touch switches according to the switch principle, and are divided into single live wire touch switches and two-wire touch switches according to the wiring method.

The mainstream technology of touch-sensitive panels is realized by using capacitive sensing technology. Because the capacitance change caused by the finger on the sensing plate is very small, and as the thickness of the isolated insulating panel increases, the magnitude of the capacitance decreases exponentially. After about 5mm of tempered glass, the touch of a human finger can only bring about a capacitance change of less than 0.5PF. For such a small amount of measurement, humidity, temperature changes, electromagnetic interference, power supply interference, etc. will greatly affect the measurement results of the measurement circuit.