A manufacturing plant has a fire alarm system that requires a minimum of 20VDC for operation. The system is powered by a 120VAC transformer. What is the minimum transformer rating required if the system draws 5A?

Exam tip

Always round up when calculating transformer ratings to ensure the transformer can handle the full load.

Why D is correct

The transformer rating is calculated by multiplying the voltage by the current. In this case, the transformer needs to provide 20V x 5A = 100VA. The closest option is 120VA, but since the transformer must be able to handle the full load, the correct answer is 1200VA to ensure it can handle the system's requirements.