Transformer power ratings can be expressed in which of the following units?

Transformer power ratings can indeed be expressed in various units, which is why the most comprehensive answer would be that they can be represented in any of the provided options.

Transformers are typically rated in volt-amperes (VA) because VA takes into account both voltage and current in an AC circuit, indicating the apparent power without considering the phase angle between the current and the voltage. This is important in AC systems due to the nature of how power is consumed.

While watts (W) represent real power and can be applicable in certain contexts, particularly when dealing with resistive loads, it's essential to recognize that transformer ratings often encompass more than just the real power aspect.

Amperes (A) can also be relevant because knowing the current rating is crucial when designing electrical systems. This allows electricians and engineers to calculate how much current can safely flow through the transformer, ensuring safe operation.

Thus, since transformers can be rated in VA, watts, and even amperes, it's accurate to say that transformer power ratings can be expressed in any of these units, providing flexibility in how electrical power can be represented based on the needs of the circuit or the application at hand.