sekundaarikäämillä

A secondary coil, or sekundaarikäämillä in Finnish, is a fundamental component in electromagnetic induction. It is typically a coil of wire wrapped around a core, often the same core as a primary coil. When an alternating current flows through the primary coil, it generates a changing magnetic field. This changing magnetic field then passes through the secondary coil, inducing an electromotive force (voltage) across its terminals. This phenomenon is governed by Faraday's law of induction.

The relationship between the voltage induced in the secondary coil and the voltage applied to the primary coil depends on the ratio of the number of turns in each coil. This principle is exploited in transformers, where secondary coils are used to step up or step down voltages. In a step-up transformer, the secondary coil has more turns than the primary coil, resulting in a higher output voltage. Conversely, in a step-down transformer, the secondary coil has fewer turns, producing a lower output voltage.

Beyond transformers, secondary coils are found in various electrical devices. They play a role in alternators, generators, inductors, and certain types of sensors. The design and construction of a secondary coil are critical for its intended application, influencing factors such as inductance, resistance, and its ability to efficiently interact with the magnetic field generated by the primary coil. The materials used for the wire and the core, as well as the winding technique, all contribute to the coil's performance characteristics.