Some advanced heating elements used in very high-temperature furnaces (e.g., silicon carbide or molybdenum disilicide) cannot be connected directly to the main power line and require a step-down transformer. In this setup, the power controller is used to precisely regulate the power going into the primary side of the transformer. This is a very efficient and stable way to control the transformer's output, which in turn provides the exact low-voltage, high-current power needed to heat the elements and achieve extreme temperatures.
