How inductor works | GETWELL

An inductor is a passive electronic component that stores electrical energy in the form of magnetic flux.

Usually the wire is wound, and when a current is passed, a magnetic field is generated from the right side of the current flowing direction.

The calculation formula of the inductance value is as follows.

inductance value

The more the number of rolls, the stronger the magnetic field.

At the same time, the cross-sectional area becomes large, or changing the magnetic core can enhance the magnetic field.

What happens to the AC current over-inductance?

AC is the current that changes periodically as the magnitude and direction of the current changes.

When the alternating current passes through the inductor, the magnetic field generated by the current cuts off the other windings, thus generating a reverse voltage that hinders the current change.

In particular, when the current suddenly increases, the electromotive force in the opposite direction to the current, that is, in the direction of current reduction, is generated to hinder the increase in current.

Conversely, when the current decreases, it is generated in the direction in which the current increases.


If the direction of the current is reversed, the reverse voltage will also be generated.

Before the current is blocked by the reverse voltage, the current flow reverses and the current cannot flow.

On the other hand, since the direct current does not change in current, there is no reverse voltage and there is no danger of short circuit.

That is to say, the inductor is a component that allows direct current to pass through and does not pass through the alternating current.


  • Electrical energy is stored in the form of magnetic energy
  • Passing direct current and alternating current cannot pass

Inductance Formula

Load its inductance and calculate the coil formula as follows

Impedance (ohm) = 2 * 3.14159 * F (operating frequency) * inductance (mH), set to use 360 ​​ohm impedance, therefore:

Inductance (mH)=impedance (ohm)÷(2*3.14159)÷F(operating frequency)=360÷(2*3.14159)÷7.06=8.116mH

According to this, the number of windings can be calculated:

Number of turns = [inductance * {(18 * circle diameter ) + (40 * circle length )}] circle diameter 

Number of turns = [8.116*{(18*2.047)+(40*3.74)}]÷2.047=19 laps

Hollow inductance calculation formula: L(mH)=(0.08D.D.N.N)/(3D+9W+10H)

D------coil diameter

N------ coil turns

d-----wire diameter

H----coil height

W----coil width

The units are mm and mH respectively. .

Types of Air Core Coils


Post time: May-09-2019