What describes the primary winding of a transformer?

The primary winding of a transformer is indeed the input winding that is connected across a power line. In a transformer, the primary winding receives alternating current (AC) voltage from the power source, and this winding generates a magnetic field in the transformer's core. This magnetic field then induces voltage in the secondary winding, which is where the output voltage is taken.

Understanding the role of the primary winding is crucial for anyone working with transformers, as it directly relates to how the transformer operates in converting voltages. This knowledge is essential for troubleshooting and maintenance within electrical and aircraft systems, where transformers are commonly used to manage voltage levels for various components.

The other statements refer to different aspects of transformers or related concepts. The primary winding does not connect directly to the load, nor does it perform the function of stepping down voltage itself—that function is more associated with the overall transformer design, depending on the turns ratio of the primary to secondary windings. Additionally, the primary winding does not store electrical energy; instead, it plays a critical role in generating the magnetic field necessary for the transformer’s operation.