In a transformer, which part contains the coil of wire that steps up or down the voltage of the original alternating current?

In a transformer, the secondary coil is crucial because it is the winding that either steps up or steps down the voltage of the alternating current that is applied to the primary coil. When an alternating current flows through the primary coil, it generates a magnetic field that induces a voltage in the secondary coil.

If the transformer is designed to step up the voltage, the secondary coil will have more turns of wire compared to the primary coil. Conversely, if the transformer is stepping down the voltage, the secondary coil will have fewer turns than the primary coil. This relationship between the number of turns in the primary and secondary coils determines the voltage transformation ratio.

The core's purpose is to enhance the magnetic coupling between the coils, but it does not contain any wire. The primary coil is where the input voltage is applied, and the transformer circuit refers to the entire assembly including connections and other components. However, it is the secondary coil that directly affects the output voltage level based on the transformer's design and specifications.