What is the relationship between the number of turns in the coils of a step-up transformer and voltage?

• A. The more turns in the secondary coil, the lower the voltage
• B. The more turns in the primary coil, the higher the voltage
• C. The more turns in the secondary coil, the higher the voltage
• D. There is no relationship between turns and voltage

Answer: (C)

In a step-up transformer, the relationship between the number of turns in the coils and the voltage is governed by the basic principles of electromagnetic induction. Specifically, the voltage across the coils is directly proportional to the number of turns. When there are more turns in the secondary coil compared to the primary coil, the transformer increases the voltage.

This occurs because the transformer operates on the principle of conservation of energy. The input power (voltage times current) must equal the output power (voltage times current) in an ideal transformer (neglecting losses). Thus, if the secondary coil has more turns, it generates a higher voltage. This equation can be expressed as:

[ V_p / V_s = 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 coil, and ( N_s ) is the number of turns in the secondary coil. When ( N_s ) (the number of turns in the secondary) is greater than ( N_p ) (the number of turns in the primary), it results in a higher voltage in the secondary coil.

This fundamental relationship underscores how transformers work in