Helmholtz coil

physics

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Last updated

July 23, 2026

Quick Summary

A Helmholtz coil consists of two equal, parallel, coaxial circular coils. These coils are connected in series and are separated by a distance equal to the radius of one coil. This arrangement is designed to produce an approximately uniform magnetic field in the space between them.1

This configuration is useful for creating controlled magnetic environments for experiments, such as canceling out external fields like Earth's magnetic field. The principle behind coils generating magnetic fields is that electric currents flowing through a wire create these fields, as described by the Biot-Savart law.234

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magnetism
Magnetization effects in matter
…a configuration is called a Helmholtz coil. By carefully orienting and adjusting the current in a large Helmholtz coil, it is often possible to cancel an external magnetic field (such as Earth’s magnetic field) in a region of space where experiments require the absence of all external magnetic fields.
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…a configuration is called a Helmholtz coil. By carefully orienting and adjusting the current in a large Helmholtz coil, it is often possible to cancel an external magnetic field (such as Earth’s magnetic field) in a region of space where experiments require the absence of all external magnetic fields.
Read More