Oersted: The historical unit for magnetic field strength

Oersted (Oe) is a historical unit for measuring magnetic field strength ( H ). It was named after the Danish physicist Hans Christian Ørsted, who discovered in 1820 that an electric current can generate a magnetic field. This was a groundbreaking discovery that demonstrated the relationship between electricity and magnetism and led to the development of electromagnetism.

Definition of the Oersted unit

The Oersted unit describes the strength of a magnetic field. Formally, it is defined as follows:

1 Oersted = 1 Dyne per Maxwell

This corresponds to a magnetic field strength at which a force of 1 Dyne acts on a magnetic monopole charge of 1 Maxwell. In the metric system, the oersted can be converted into SI units:

1 oersted ≈ 79.577 amperes per metre (A/m)

Although the oersted is historically significant, it is now replaced by the SI unit amperes per metre (A/m) in most scientific and technical applications.

The importance of Hans Christian Ørsted

Hans Christian Ørsted was a Danish physicist and chemist who discovered in 1820 that an electric current can generate a magnetic field. His experiment showed that a current-carrying wire deflects a compass needle. This discovery laid the foundation for the development of the theory of electromagnetism by scientists such as James Clerk Maxwell and André-Marie Ampère.

Applications of the Oersted

Although the Oersted is rarely used today, it remains of historical and practical interest in certain areas:

• Magnetic materials: In older documentation and specifications of magnets, the field strength is often given in Oersted.
• Technical literature: In countries with non-metric systems, the oersted is sometimes still used in literature.
• Historical research: Studies on the development of magnetism and electromagnetism often refer to the discovery of Ørsted and the introduction of the unit.

Interesting facts about Oersted

Did you know that Ørsted's discovery of electromagnetism forms the basis for modern technologies such as electric motors, generators and transformers? Without his findings, many of today's electrical devices and applications would be unthinkable. The Oersted unit remains an important symbol for the beginning of the understanding of the relationship between electricity and magnetism.