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Choke as an electrical engineering component  

A traditional choke is usually comprised of a coil and an iron core with an air gap. When alternating voltage is fed into the coil, the strength of the electrical power in the coil also changes. The coil creates an alternating magnetic flux in the iron core. This alternating magnetic flux creates an intermittent alternating electromotive force that is opposite to the voltage affecting the coil. The electromotive force resists the alternation of the current in the coil. Choke with a laminated core is the most traditional inductor structure.

Each coil has its own structure-specific self-induction factor or inductance (L).

The SI unit name for inductance is Henry and its symbol is H (H = Vs/A).

The inductance value is proportional to both the number of effective turns squared and the magnetic circuit's resistance. The magnetic circuit's resistance is called Reluctance (Rm).

kuristin havainnekuva

A toroidal choke is made by manufacturing the core from iron dust or ferritic materials.


  • switching power supply
  • mains interference filter

Differnetiaali- ja virtakompensoitu kuristin

On the left a current-compensated inductor and on the right a differential form inductor.

Self-inductance is used in electrical engineering, but it can also be harmful.


  • an inductor levels out current fluctuation in e.g. fluorescent and discharge lamps
  • inductors are used in filter circuits and interference removal


  • an inductor causes sparks between the switch and contact tips when circuits with inductive components are disconnected

Intertrafo's inductors

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