The most common function of an inductor in a circuit is to form an LC filter circuit together with a capacitor. We already know that capacitors have the ability to "block DC and pass AC", while inductors have the function of "pass DC and block AC". If the direct current accompanied by many interference signals is passed through the LC filter circuit (as shown in the figure), then the AC interference signal will be consumed by the capacitor as heat; when the pure DC current passes through the inductor, the AC interference signal in it will also be Turned into magnetic induction and heat energy, the higher frequency is most likely to be impedance by the inductance, which can suppress the higher frequency interference signal.

 

 

The inductance of the power supply part of the circuit board is generally made of a very thick enameled wire wrapped around a round magnetic core coated with various colors. Moreover, there are generally several tall filter aluminum electrolytic capacitors nearby, and the two constitute the above-mentioned LC filter circuit. In addition, the circuit board also uses a large number of "snake lines + chip tantalum capacitors" to form an LC circuit, because the snake line folds back and forth on the circuit board, which can also be regarded as a small inductance.