Understand the function of inductors and the functions and USES of inductors

Inductance a device used to provide inductance. Various coils wound around an insulated wire are called inductance. Its main role is to block ac through dc, blocking high frequency through low frequency, that is to say, high frequency signal through the inductance coil will encounter a great resistance, it is difficult to pass, and low frequency signal through it when the resistance is relatively small, that is, low frequency signal can easily pass through it. The resistance of an inductance coil to direct current is almost zero.

Classification of inductance

1. According to the property of magnetic body, it is divided into hollow coil, ferrite coil, iron coil and copper coil.

2, according to the working nature of the classification: antenna coil, oscillating coil, choke coil, trap coil, deflection.

3, according to the winding structure classification: single-layer coil, multi-layer coil, honeycomb coil. High frequency SMT ceramic inductance

4. Classification by inductance: fixed inductance coil, variable inductance coil.

5. According to the structure characteristics: magnetic core coil, variable inductance coil, color code inductance coil, core-free coil, etc.

In addition, often according to the working frequency and over current, divided into high frequency inductance, power inductance.

Basic use of inductors

1, the role of the inductor is mainly through dc, resistance to ac, in the circuit mainly plays a filtering, oscillation, delay, trap and other functions. The inductance coil has a blocking effect on the ac current. The magnitude of the blocking effect is called inductive reactance XL, and the unit is ohm. The relation between it and inductance L and ac frequency f is XL=2 fL. Inductors can be mainly divided into high frequency choke coil and low frequency choke coil. Tuning and frequency selection: LC tuning circuit can be formed by shunt inductance coil and capacitor. That is, the natural oscillation frequency of the circuit f0 is equal to the frequency f of the non-ac signal, so the inductive reactance and capacitive reactance of the circuit are also equal, so the electromagnetic energy oscillates back and forth in the inductance and capacitance, which is the resonance phenomenon of the LC circuit. When resonant, the inductive reactance and capacitive reactance of the circuit are equivalent and reverse, the inductive reactance of the circuit's total current is the smallest, and the current flow is the largest (refers to the ac signal f="f0"). LC resonance circuit has the function of selecting frequency, which can select the ac signal of a certain frequency f.

2. Inductors have functions of filtering signals, filtering noises, stabilizing current and inhibiting electromagnetic interference. In electronic equipment, often see some circular, this circular form an inductor with connecting cable (cable wire around a few rounds in the circular of inductance coil), it is commonly used in electronic circuit anti-interference components, high frequency noise with good shielding effect, so it is called absorption of copper, ferrite materials are often used, is also called the ferrite beads (hereinafter referred to as the circular). Magnetic rings have different impedance characteristics at different frequencies. At low frequencies the impedance is very small, and as the signal frequency increases the impedance of the magnetic ring increases dramatically.