In transformers, what does the primary coil do?

The primary coil in a transformer is crucial for the functioning of the device, as it is responsible for receiving input voltage from the electrical source. When alternating current (AC) flows through the primary coil, it generates a magnetic field. This magnetic field then induces a voltage in the secondary coil, which transforms the input voltage to a different level based on the turns ratio between the primary and secondary coils.

Understanding this process is important because it highlights the primary coil's role as the starting point for energy transformation within the transformer. It does not deliver the output voltage to the load; that function is performed by the secondary coil. Additionally, the primary coil does not convert AC to DC, nor does it store electrical energy; those functions fall outside the operation of a transformer. The correct understanding of the primary coil's role is essential in the study of how transformers operate in electrical systems.