What is the function of a variable transformer?

A variable transformer, commonly known as a variac, is designed to provide adjustable voltage levels from a fixed input. This means that it allows users to change the output voltage by altering the transformer’s tap connections, effectively providing different amounts of voltage based on user requirements. This feature is particularly useful in experiments, equipment testing, or any situation where varying voltage is needed without changing the power source.

While some other devices are designed to convert AC to DC, maintain consistent voltage, or isolate circuits, those functions do not align with the primary purpose of a variable transformer. The focus of a variable transformer is fundamentally on adjusting the output voltage, making it a versatile tool in a variety of electrical applications.