In a transformer, what does the turns ratio help to determine?

The turns ratio in a transformer is a critical factor that helps determine the relationship between the primary and secondary voltages and turns. The turns ratio is defined as the ratio of the number of turns in the primary winding to the number of turns in the secondary winding. By this relationship, if the transformer is known to have a certain number of turns on the primary and a specific voltage on the secondary, one can deduce the number of turns on the primary for a particular output voltage.

When considering the formula for a transformer:

[ \frac{V_p}{V_s} = \frac{N_p}{N_s} ]

where (V_p) is the primary voltage, (V_s) is the secondary voltage, (N_p) is the number of turns in the primary winding, and (N_s) is the number of turns in the secondary winding, the turns ratio allows us to manipulate the equation to find unknown values, whether it's voltage or turns. Thus, knowing the secondary voltage and the turns ratio aids in calculating how many turns are required in the primary winding.

This is why the option concerning determining primary turns based on secondary voltage accurately reflects the functionality of the turns ratio within the context of transformer operation