Which of the following is not a type of electrical protective device?

A transformer is a device used to transfer electrical energy between two or more circuits through electromagnetic induction, typically to change voltage levels. While transformers play a critical role in electrical systems by increasing or decreasing voltage for transmission and distribution purposes, they do not serve the function of protecting electrical circuits from faults or overloads.

In contrast, protective devices like fuses, circuit breakers, and surge protectors are specifically designed to guard electrical systems against overcurrent, short circuits, and voltage surges. Fuses interrupt the circuit when current exceeds a certain threshold, circuit breakers can be reset after tripping, and surge protectors help protect devices from voltage spikes. Understanding the distinct functions of these devices is essential for recognizing the role each plays in maintaining electrical safety and reliability.