sekundaarikäämi
A sekundaarikäämi, which translates to "secondary coil" in English, is a fundamental component in electromagnetic induction devices, most notably transformers. It is essentially a coil of wire wound around a core, often made of ferromagnetic material, which is separate from the primary coil. The interaction between the primary and secondary coils, mediated by a changing magnetic field, is the basis of how transformers function. When an alternating current flows through the primary coil, it creates a fluctuating magnetic field. This changing magnetic field then passes through the core and induces an electromotive force (voltage) in the secondary coil. The ratio of the number of turns in the primary coil to the number of turns in the secondary coil determines the voltage transformation. If the secondary coil has more turns than the primary, it's a step-up transformer, increasing the voltage. Conversely, if it has fewer turns, it's a step-down transformer, decreasing the voltage. The secondary coil's design and material are crucial for efficient energy transfer and are chosen based on the specific application requirements of the transformer, such as power handling capacity and operating frequency.