The magnetic loop coil is an element made according to the principle of magnetic induction. Inductance in electronic equipment is divided into two categories: one is an inductance coil with self-inductance function, and the other is a transformer or transformer with mutual inductance function. Inductance is formed by winding a certain number of insulated wires on an insulated frame. When DC passes through the coil, the DC resistance is the resistance of the different wires themselves, and the voltage drop is very small. When an AC signal passes through the coil, an internal electromotive force will be generated at both ends of the coil. The direction of self-induced electromotive force is opposite to the direction of applied voltage, which hinders the passage of AC. Therefore, the characteristic of inductance is to prevent AC from passing through DC. The higher the frequency, the greater the impedance of the coil.

The magnetic loop coil is also called a pulse transformer. The quality factor is the main parameter for measuring inductive components. When the inductor works at AC voltage frequency, the magnetic loop coil refers to the ratio of the inductance to its equivalent DC resistance. The larger the number of high-quality flashes of the inductor, the smaller the loss and the higher the efficiency.