What is an inductor? What is the function of the inductor?

Cuộn cảm

Inductors are an important electronic component in electrical devices, electronic circuits, and electronic boards. So what function does this component play in electrical circuits and electronic boards? Follow along with the article below to get answers to questions related to inductors!

Learn about inductors

What is an inductor?

An inductor is a passive electronic device made from an electrical conductor with several turns around it. When an electric current flows through it, a magnetic field is generated, and the core is a magnetic conductive material or engineering steel. Based on structure and use, chokes are divided into 3 main types: negative-frequency chokes, mid-frequency chokes, and high-frequency chokes.



Inductors are made up of many turns of wire wound together. The type of wire wrapped around it will be epoxy-painted for good electrical insulation effect. In addition, the coil core is made from many different materials, such as air, magnetic conductive materials such as ferrite, steel core, etc.

Working principle

The operation of the inductor depends on the AC or DC current and the frequency level of the current.

When the DC current passes through with a constant current and direction (zero frequency), then the inductor will act as a short-circuit connection coil with zero impedance.

If there is an AC current passing through the inductor, then the current in the inductor will produce a type of magnetic field B capable of varying with the electric field E. Then there is the frequency of the alternating current. AC will affect the inductance level of the inductor.


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– Coefficient of inductance

The inductance of the inductor is denoted L, and the unit of measure is H (Henry). This is the characteristic quantity of the electromotive force induced by the coil when there is a change in the current.

L = ( µr.4.3,14.n2.S.10-7 ) / l

In there:

  • L : is the inductance of the coil
  • n : is the number of turns of the inductor winding
  • l : is the coil length (m)
  • S : is the cross-section of the core (m2)
  • µr : is the magnetic permeability coefficient of the inductor core material.


The inductance of an inductor is a measure of the resistance of the coil to alternating current.

ZL = 2.314.f.L

In there:

  • ZL: inductance (Ω)
  • f : frequency (Hz)
  • L: inductance coefficient (H)

The main functions of the inductor

In electronic circuits, inductors are electronic components that have the following roles:

  • High-frequency current blocking in electrical circuits is mainly used in electronic filters to separate signals containing different frequencies.
  • connected in series or parallel with a capacitor to form a resonant circuit, used to regulate devices such as televisions, radios, etc.
  • Blocking AC while passing DC


Applications of inductors

Based on that function, inductors have been widely applied to the following devices:

Electromagnetic Role

The electromagnetic relay through the coil will turn the current into a magnetic field, and from this magnetic field, through the suction force to open and close the switch, open and close the device automatically.

Proximity sensor

Proximity sensors use inductors to detect nearby objects without the need for physical contact. This operation is based on the principle that when current flows, the inductor creates a magnetic field around it or any change when the inductor in the magnetic field induces an induced current.

The inductor in the regulator circuit

In radio and television stations, inductors combine with capacitors in the tuning circuit to be able to select the desired broadcast channel.

Noise filter choke

Inductors, together with resistors and capacitors, are indispensable components in various frequency filters, such as high-pass, low-pass, and band-reject filters. These are frequency filters to separate unnecessary frequency components from the signal.

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Above is an overview of the structure, characteristic quantities, classification, and uses of inductors. Hopefully, through the article, everyone has learned useful information related to this type of component. The Tech is a supplier with the mission of being a bridge between manufacturers of materials and components for electronic assembly plants. We always provide our customers with high-tech, high-quality, safe material products that comply with European safety regulations (RoHS) and with IPC manufacturing processes. For advice, The best thing to do is contact us!

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