In a power transformer, which statement about the primary winding is accurate?

• A. The winding connected to the load.
• B. The winding that carries AC current.
• C. The winding with the fewer turns.
• D. The winding connected to the source.

Answer: (D)

The primary winding is defined by its connection to the source. It is the winding that the input AC voltage is applied to, and it creates the alternating magnetic flux in the core that links to the other winding. The secondary winding is the one connected to the load and delivers the transformed voltage to the load. The number of turns or the current in each winding depends on the transformer's design and whether it steps voltage up or down, so those features aren’t the defining characteristic.