Heating, Ventilation, and Air Conditioning (HVAC ) Electrical Practice Test

A step-up transformer performs which of the following functions?

1. Decreases voltage

2. Increases voltage

3. Changes frequency

4. Converts AC to DC

The correct answer is: Increases voltage

A step-up transformer increases voltage while maintaining the same power level. This type of transformer has more turns of wire on the secondary coil compared to the primary coil, which allows it to convert a lower voltage from the primary side to a higher voltage on the secondary side. The principle behind this function is rooted in electromagnetic induction, where the voltage change is proportional to the number of turns in each coil according to the transformer equation. In practical applications, step-up transformers are often used in power distribution systems to raise the voltage for efficient long-distance transmission. This ensures that less energy is lost as heat in the conductors. Other options suggest functions like decreasing voltage, changing frequency, or converting AC to DC, none of which correctly describe the operation of a step-up transformer. Decreasing voltage is the role of a step-down transformer, while changing frequency is not a function of transformers in general; those are typically managed by other types of equipment. Lastly, converting AC to DC is a function handled by rectifiers, not transformers.