Which one of the folio whig devices changes low voltage alternating cuiTent to high voltage alternating current and vice versa ?

A transformer is a static electrical device that transfers alternating current (AC) power between circuits using electromagnetic induction. It is specifically designed to change voltage levels while maintaining the same frequency. A 'step-up' transformer increases low voltage from the primary side to high voltage on the secondary side, which is essential for long-distance power transmission to minimize energy loss [1]. Conversely, a 'step-down' transformer reduces high voltage to lower, safer levels for distribution and consumer use. While generators produce electricity and motors convert electrical energy into mechanical work, only the transformer is used to step voltage up and down within AC systems [1]. This conversion relies on the ratio of wire turns in the primary and secondary coils.

Sources

1. [1] https://www.britannica.com/technology/transformer-electronics