Which type of transformer has a turns ratio greater than 1?

• A. Step-down transformer
• B. Isolation transformer
• C. Step-up transformer
• D. Variable transformer

Answer: (C)

A transformer with a turns ratio greater than 1 is classified as a step-up transformer. This type of transformer increases the voltage from the primary winding to the secondary winding. The turns ratio is defined as the ratio of the number of turns in the primary coil to the number of turns in the secondary coil. When this ratio is greater than 1, it indicates that there are more turns in the secondary coil compared to the primary coil, resulting in a higher output voltage.

In practical applications, step-up transformers are commonly used in power transmission systems to elevate the voltage, thereby reducing losses over long distances. This is essential for efficient electrical power distribution.

Other transformer types, such as those specifically designed for isolation or variable applications, do not inherently have a turns ratio greater than 1. An isolation transformer, for example, typically has a turns ratio of 1:1 to safely isolate the output from the input. A step-down transformer reduces voltage by having more turns in the primary coil compared to the secondary coil, which creates a turns ratio less than 1. Variable transformers allow for adjustment of the output voltage but do not strictly follow the characteristic of having a turns ratio greater than 1.