How does a typical distribution transformer function?

• A. It converts DC to alternating current
• B. It increases current while decreasing voltage
• C. It stores energy in a magnetic field
• D. Primary voltage applied to the primary winding induces a voltage in the secondary winding

Answer: (D)

A distribution transformer works on electromagnetic induction. When alternating current is applied to the primary winding, it creates a changing magnetic flux in the core. This changing flux links the secondary winding and induces a voltage there, with the magnitude set by the turns ratio. Because the device is designed for AC, a steady DC would not produce a continuous induced voltage after the initial transient. The transformer transfers energy magnetically from primary to secondary, and the secondary current adjusts with the load to keep the input and output powers close (minus losses). So describing the mechanism as the primary voltage inducing a voltage in the secondary winding directly captures how a typical distribution transformer operates.