Inductance is the phenomenon by which a conductor opposes changes in the current flowing through it; it is defined as the ratio of the induced voltage to the rate of change of the current that produces it. The dimensional formula for inductance is ML²T⁻²I⁻², and its SI unit is the henry (H). An inductance of 1 H signifies that a current changing at a rate of one ampere per second induces a voltage of one volt.
The fundamental nature of inductance lies in the relationship described by Maxwell's equations regarding the generation of an electric field by a changing magnetic field. When the current in a conductor changes, the associated magnetic field also changes; in accordance with Faraday's law of electromagnetic induction and Lenz's law, this generates an electromotive force (EMF) that opposes the change in current. Wireless charging utilizes near-field induction-specifically, inductive coupling-to transfer energy.
The term "inductance" was coined by Oliver Heaviside in May 1884. my country's primary inductance standard device was developed starting in 1971, completed in 1975, certified in 1979, and participated in the CCEM-K3 international comparison in 1990. Sunlord Electronics filed a patent in 2025 for an inductive component capable of combining high inductance with a high quality factor.
