Vaihtojännitelähteet

Vaihtojännitelähteet are electronic devices that convert a stable AC voltage to a variable AC voltage. They are fundamental components in many electronic systems, enabling control over the amplitude of alternating current signals. The primary mechanism by which most vaihtojännitelähteet operate involves transformers. A transformer consists of two or more coils of wire wound around a common iron core. When an alternating current flows through the primary coil, it generates a changing magnetic field in the core. This changing magnetic field then induces an alternating current 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, the output voltage will be higher (step-up transformer). Conversely, if the secondary coil has fewer turns, the output voltage will be lower (step-down transformer). Some vaihtojännitelähteet employ autotransformers, which have a single winding acting as both primary and secondary. This allows for a more compact and efficient voltage adjustment, particularly for smaller voltage variations. The output voltage of a vaihtojännitelähde can be adjusted either by physically changing the number of active turns in the secondary winding, as in a variac (variable autotransformer), or by using electronic control circuits that manipulate the input signal or the transformer's operation. These devices are crucial for applications requiring flexible voltage control, such as in laboratory power supplies, dimmers for lighting, and industrial motor speed controllers.