What is the role of a transformer in a residential electrical system?

• A. To combine different electrical loads
• B. To step up or step down voltage levels
• C. To store electrical energy
• D. To convert AC to DC

Answer: (B)

The role of a transformer in a residential electrical system is primarily to step up or step down voltage levels. This function is crucial for the efficient transmission and distribution of electrical power.

In an electrical system, high voltage is utilized for transmission over long distances because it reduces energy loss as heat. However, once the electricity reaches the residential area, it needs to be stepped down to a lower voltage that is safe and usable for household appliances, typically at 120 or 240 volts.

Transformers achieve this voltage transformation without changing the frequency of the electrical supply. By adjusting the number of wire turns in the primary and secondary coils, transformers can increase (step up) or decrease (step down) the voltage levels accordingly. This ability is essential for maintaining safety and efficiency in the electrical system.

Other options, like combining different electrical loads, storing electrical energy, or converting AC to DC, do not accurately reflect the primary function of a transformer in residential systems. Those roles are typically managed by different devices or technologies within the electrical infrastructure.