What type of transformer is referred to as a step down transformer?

A step-down transformer is specifically designed to reduce voltage from primary to secondary windings. This type of transformer has a higher number of turns in the primary coil compared to the secondary coil. As a result, when alternating current flows through the primary winding, it produces a magnetic field that induces a lower voltage in the secondary winding due to the fewer turns.

This function is crucial in various applications, such as power distribution, where high transmission voltages need to be reduced to safer, usable levels for residential or commercial use. When the secondary voltage is lower than the primary voltage, it allows for a step-down in voltage that is necessary to power devices safely and effectively.

The other options describe characteristics that do not align with the definition of a step-down transformer. A transformer with higher secondary voltage would indicate a step-up transformer, while variable secondary voltage would not describe the fixed output of a step-down model. Lastly, constant primary voltage doesn't specifically categorize the transformer type but rather describes the conditions under which it operates.