Characteristics and functions of inductors

An inductor is a component that can convert electrical energy into magnetic energy and store it. The structure of an inductor is similar to that of a transformer, but it only has one winding. An inductor has a certain inductance that only hinders changes in current. If the inductor is in a state where there is no current flowing, it will attempt to block the flow of current when the circuit is connected; If the inductor is in a state with current flowing through it, it will attempt to maintain the current constant when the circuit is disconnected. Inductors, also known as chokes, reactors, and dynamic reactors.

characteristic

The characteristics of an inductor are exactly opposite to those of a capacitor, as it has the characteristic of preventing the passage of alternating current and allowing direct current to pass smoothly. The resistance of the DC signal passing through the coil is the resistance of the wire itself, and the voltage drop is very small; When an AC signal passes through a coil, a self induced electromotive force will be generated at both ends of the coil. The direction of the self induced electromotive force is opposite to the direction of the applied voltage, hindering the passage of AC. Therefore, the characteristics of an inductor are to pass DC and resist AC, and the higher the frequency, the greater the impedance of the coil. Inductors often work together with capacitors in circuits to form LC filters, LC oscillators, etc. In addition, people also use the characteristics of inductance to manufacture resistance coils, transformers, relays, etc.

Direct current: Refers to the inductor being in a path closed state towards direct current. If the resistance of the inductance coil is not taken into account, direct current can pass through the inductor smoothly. For direct current, the resistance of the coil itself is very small and has little obstruction to direct current, so it is often ignored in circuit analysis.

Resistance to AC: When AC power passes through an inductor coil, the inductor has a blocking effect on AC power, and what hinders AC power is the inductance of the inductor coil.

Functional purpose

Inductors mainly play roles in circuits such as filtering, oscillation, delay, and notch, as well as filtering signals, filtering noise, stabilizing current, and suppressing electromagnetic interference. The most common function of an inductor in a circuit is to form an LC filter circuit together with a capacitor. Capacitors have the characteristic of "blocking DC and blocking AC", while inductors have the function of "blocking DC and blocking AC". If direct current with many interference signals is passed through an LC filtering circuit, the AC interference signal will be converted into thermal energy by inductance and consumed; When a relatively pure DC current passes through an inductor, the AC interference signal in it is also converted into magnetic induction and thermal energy. The higher frequency is most likely to be impedance by the inductor, which can suppress the higher frequency interference signal.

Inductors have the characteristic of preventing the passage of alternating current and allowing direct current to pass smoothly. The higher the frequency, the greater the coil impedance. Therefore, the main function of an inductor is to isolate and filter AC signals, or to form a resonant circuit with capacitors, resistors, etc.