What Is a Variac?
A variac, or variable autotransformer, uniquely adjusts voltage in electrical circuits, differing from fixed transformers by providing a variable output voltage. It achieves this through a single, continuously wound coil on a toroidal core, with a movable brush that taps the winding at different points to vary the output voltage.
This capability makes variacs especially useful in alternating current (AC) applications for precise control over voltage, such as in laboratory testing, equipment calibration, and anywhere variable supply is needed. Though primarily designed for AC, special configurations can adapt variacs for direct current (DC) use.
The key benefit of using a variac is its unparalleled precision in voltage control, allowing for the seamless adjustment of voltage levels to meet specific requirements of electronic devices and systems during testing or development.