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Chokes are inductive components in the electrotechnics and are used for interference suppression, commutation, energy storage and current limitation.
Solid iron or ferrite cores of chokes are frequently provided with an air-gap to avoid the core saturation. The air-gap is an interruption of the magnet core and is often filled out with nonmagnetic material as paper, plastic or resin to stabilize the core mechanically. Iron chokes are used in series chokes (inductive series resistor) of gas discharge lamps or in mains filters.
Current compensated chokes
The current compensated choke or common mode choke has several similar windings which are flowed through by the working current reversely so that the magnetic fields cancel themselves out in the core of the choke. They are frequently used for the recession by disturbing issues. Such interfering currents usually are common fashion in for and back line. Current compensated chokes often are used at inputs and outputs of switched mode mains power supplies as well as in line filters.
Ring core chokes
Ring core chokes are mode of ferrite or are produced as powder ring cores. Ring cores form a closed magnetic circle and therefore show only low magnetic stray fields. A low spread contributes to the better electromagnetic compatibility EMC.
Saturation chokes make use of the effect of the saturation of the core material. They limit the current rise speed at the beginning of the current flow and loose their inductance almost complete when the saturation starts.