The term "choke" is often used as a synonym for an inductance that influences the electric current. A choke coil can have various forms, including air coils or coils with a core of magnetic material such as iron or ferrite. The main function of a choke coil is to limit or regulate alternating current by providing resistance to alternating current. The term "choke" is more commonly used in German-speaking regions, while in other regions the term "inductor" is more common.

The coil's mode of operation is based on the fact that a conductor through which an electric current flows generates a magnetic field. The coil is reached through the wound conductor via the conductor loop. Inside the coil there is a largely homogeneous (optimized design for Intertechnik coils) magnetic field B (unit Tesla), which runs in one direction for the specified direction of current flow. A reversal or constant change in the current, as occurs in music systems, results in a constant change in the magnetic field. Here the coil shows an interesting behavior. A changing magnetic field (change in flux density) causes an induction voltage in the coil's own windings, which has a delaying effect on the change in current strength that it generates. The faster the change in current direction occurs (high frequencies), the more pronounced this effect is. The coil then acts like a resistor. This alternating current resistance of a coil is also referred to as inductive resistance. The electrical quantity that describes the coil effect is the inductance L (unit of measurement Henry). In addition to the inductive resistance, the coil has a further resistance (direct current resistance or DC resistance), which results from the limited conductivity of the wound wire. In the audio frequency range, an air-core coil can largely be described by the inductance L and the DC resistance R.