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An inductor is a passive electrical component with two terminals and is used to store energy when electric current passes through it in a magnetic field. An inductor is made of insulated wire round into a coil around the core.

Once current passes through an inductor varies, a magnetic field with time varying induces a voltage called e.m.f in a conductor around the core as stated by faraday’s law. The change of magnetic field found around an inductor corresponds to the current change. So, when the magnetic field varies, a voltage is created across the terminals of an inductor that oppose this change. Inductor is used to block AC while allowing DC to pass in a circuit.

Inductor symbol

Types of Inductor

  • Air-core inductor: air core coil is an inductor that does not use a magnetic core but instead it is made up of coils wounded on plastics or other non- magnetic forms. They have lower inductance and they are used at high frequencies because they are energy lossless.
  • Laminated-core inductor: they are inductors made with laminated cores to avoid eddy current effect. They are applied within transformers.
  • Ferrite-core inductor: There are inductors made up of ceramic ferromagnetic material that is nonconductive called ferrite so the eddy current will not pass in those inductors.
    • Toroidal-core inductor: Toroidal cores allow a minimum of the magnetic flux to escape outside the core for that reason they radiate less electromagnetic interference than other shapes. Toroidal core coils are made up of laminated cores, primarily ferrite and powdered iron.
  • Variable inductor: are inductors with moveable ferrite magnetic cores that can be slid in and out of the coil so as to increase the permeability, the magnetic field and also the inductance

    • Induction motor
    • Transformers
    • Inductive filters
    • Chokes
    • Relays
    • Ferrite beds
    • Inductive sensors
    • Inductors used in tuned circuits.