Apukäämi

Apukäämi is a Finnish term that translates to "auxiliary coil" or "helper coil." In electrical engineering, it refers to a secondary coil in an inductive coupling system, distinct from the primary coil. The primary coil is typically connected to an alternating current source, generating a magnetic field. This magnetic field then induces a current in the apukäämi, which is positioned in proximity to the primary coil.

The concept of an apukäämi is fundamental to many transformer and wireless power transfer applications. In a standard transformer, both the primary and secondary coils are wound on a common magnetic core to maximize energy transfer. However, an apukäämi can also function in systems where there isn't a direct physical connection or a shared core, such as in inductive charging pads or RFID tags.

The design and placement of the apukäämi are crucial for efficient operation. Its inductance, resistance, and the distance and orientation relative to the primary coil all affect the amount of power transferred. Apukäämi can be found in various devices, including induction cooktops, electric toothbrushes, and proximity sensors, where they play a vital role in transmitting energy or signals wirelessly.