The RC absorption circuit is also called the RC buffer circuit. It is a circuit structure in which a resistor and a capacitor are connected in series and connected in parallel with a switching device. It is used to improve the voltage and current waveforms that the electronic power device bears when it is turned on and off. The Else RC absorption loop module can prevent the induced electromotive force generated at the moment when the inductive load is turned on and off from causing damage to the switching devices such as relays and thyristors, prevent electromagnetic interference and increase the anti-interference ability of the microcontroller