The previous article talked about the development history of inductors. Next, let's take a look at the classification of inductors.
The most common inductors are classified by function:
1. EMI inductor (to eliminate noise):
(1). Differential mode noise impedance: such as BEAD / RH CORE
(2). Common mode inductor: such as COMMON MODE CHOKE
2. Power inductor (power management): such as SMD POWER INDUCTOR / DIP INDUCTOR
Common mode inductors and differential mode inductors:
The differential mode inductor is a winding (a coil wound on an iron core). The filter inductor connected separately to the neutral wire and the live wire can only filter out differential mode interference.
Differential mode inductors are particularly suited for high current applications. Because a coil wound around an iron core will saturate when the current flowing into the coil increases, the most commonly used iron core material on the market is metal powder core.
Common mode inductors are two windings (two sets of coils with equal number of turns on the same core, equal wire diameters, and wound in opposite directions).The two windings have the same input and output.Connect to the neutral wire and the live wire respectively.What is filtered out is the common mode signal.
The characteristic of common-mode inductors is that the two coils on the same core are wound in opposite directions, so the core is not afraid of saturation. The most commonly used core material on the market is high-conductivity ferrite.
Working principle diagram of differential mode and common mode inductors:
