What information is required to determine the output voltage of a transformer?

To determine the output voltage of a transformer, both the input voltage and the turns ratio are essential. The input voltage represents the initial voltage supplied to the transformer, while the turns ratio indicates the relationship between the number of turns in the primary winding (where the input voltage is applied) and the number of turns in the secondary winding (where the output voltage is derived).

The formula used to calculate the output voltage is derived from these two variables and is given by:

Output Voltage = Input Voltage × (Secondary Turns / Primary Turns)

or, equivalently,

Output Voltage = Input Voltage × Turns Ratio.

This highlights the importance of both pieces of information: without knowing the turns ratio, you cannot accurately determine how much the input voltage will be transformed in the secondary winding.

The other options either omit one of these critical elements or only focus on one of them, which is insufficient for calculating output voltage in a transformer.