Kytkentäinduktiivisuus

Kytkentäinduktiivisuus, known in English as mutual inductance, is a measure of how effectively a change in current in one coil induces a voltage in a nearby coil. It is a fundamental concept in electromagnetism and is crucial for understanding the operation of transformers, inductors, and other electromagnetic devices.

The symbol for mutual inductance is M, and its unit of measurement is the Henry (H), the same unit used for self-inductance. Mutual inductance depends on the physical characteristics of the two coils, including their size, shape, number of turns, and their relative orientation and distance. The closer and more aligned the coils are, and the more turns they have, the higher the mutual inductance will be.

The phenomenon is described by Faraday's law of induction and Lenz's law. When the current in the primary coil changes, it creates a changing magnetic flux. If this magnetic flux links with the secondary coil, it induces an electromotive force (EMF), or voltage, in the secondary coil. The magnitude of this induced voltage is directly proportional to the rate of change of current in the primary coil and the mutual inductance between the two coils.

Mutual inductance is a reciprocal property, meaning that the voltage induced in coil 2 due to a change in current in coil 1 is equal to the voltage induced in coil 1 due to the same change in current in coil 2, provided the coils are in the same configuration. This symmetrical relationship is key to transformer operation, where energy is efficiently transferred from the primary to the secondary winding via the magnetic field.