Chokes are inductive passive components in the field of electrical engineering. They are mainly used in the power supply of electrical devices or systems, in power electronics and in low- and high-frequency technology. Line chokes consist of at least one winding of a current conductor through which the full load current flows. The winding is usually wound on a coil carrier and consists of a soft magnetic core. Chokes work with so-called self-induction and can therefore be used in various areas of electrical engineering. Chokes can therefore be used for damping, radio interference suppression, commutation, current limiting, suppression of unwanted frequencies or for energy storage in switching regulators and switching power supplies.

There are a number of specific terms for chokes in electrical engineering and electronics, which have developed from the design, their application or the circuit technology.

Below is a selection of the different chokes and their functions:

Mains choke:
Limitation of the short-circuit current or starting current to a specified value. Attenuation of harmonics or interference voltage.

Smoothing choke:
Reduction of the ripple or extension of the current flow duration with pulsating direct current

Commutation choke:
Reduction of the steepness of the current rise and thus limitation of peak currents during commutation

Filter circuit choke:
Protection of compensation systems against impermissible harmonics.

Storage choke:

By using storage chokes, magnetic energy can be stored in the air gap (interruption of the magnetic circuit and thus reduction of the magnetic flux density). Storage chokes are often required for low-power switching power supplies.

Series choke:

Ballast chokes limit and stabilize the current with low loss due to the reactance and generate the necessary high ignition voltage for fluorescent lamps, for example.

Suppressor choke:

These chokes are used for radio interference suppression and should cover a very broad frequency spectrum and have a high impedance.

Current-compensated choke:

The current-compensated choke – also known as a common-mode choke – is often used to attenuate interference emissions. The magnetic field in the core of the choke is canceled out by several windings that flow in the opposite direction to the working current.

Air throttle:

Air chokes – also known as air coils – are used for very high frequencies and for crossovers in loudspeaker systems. The absence of a magnetic core means that there is no magnetic saturation, which can lead to distortion of the current. There are no eddy current and hysteresis losses. To achieve the same inductance as with core chokes, air chokes require more windings.

Saturation throttle:

The saturation choke utilizes the effect of magnetic saturation of the core material. This limits the rate at which the current rises, for example in thyristor circuits.

PFC choke:

PFC (Power Factor Correction) chokes are used to limit the harmonics of the mains supply.

non-linear loads on the AC grid. They are used as passive PFC at mains frequency or in special active PFC circuits up to 100 kHz.