CompTIA Security+ Exam Prep

Answer: C - Metal oxide varistors protect against power surges. A surge is a prolonged rise in voltage from a power source. Surges can cause a lot of damage very quickly. A surge is one of the most common power problems and is controlled with surge protectors. The metal oxide varistor moves the excess voltage to ground when a surge occurs. Its source can be from a strong lightning strike, a power plant going online or offline, a shift in the commercial utility power grid, and electrical equipment within a business starting and stopping.