Which transformer decreases voltage from primary to secondary?

• A. Step-Down
• B. Core
• C. Step-Up
• D. Isolation

Answer: (A)

Voltage change in a transformer depends on the turns ratio between the windings. When the secondary winding has fewer turns than the primary, the output voltage is lower than the input, so the device is a step-down transformer. It’s used to drop high system voltages to safer, usable levels. A step-up transformer does the opposite, increasing voltage by having more turns on the secondary. An isolation transformer mainly provides electrical separation without a significant change in voltage magnitude, and the core simply provides the magnetic path that links the windings.