Which of the following characteristics is true about metal oxide surge arresters?

Metal oxide surge arresters (MOSAs) are specifically designed to protect electrical systems from voltage transients caused by lightning strikes or switching operations. The statement that they can be gapless or have air gaps highlights an essential feature of their construction and operation.

Gapless metal oxide surge arresters use metal oxide varistors (MOVs) without any air gaps, allowing for immediate response to voltage surges, which results in efficient transient voltage suppression. This design minimizes the risk of failure due to arcing or partial discharge, which can occur with air gaps, especially during high-energy events. The presence of air gaps in other arrester designs, such as traditional silicon carbide (SiC) arresters, allows for some level of insulation under normal operating conditions, but introduces delays in response to surges. Thus, the versatility of MOSAs in utilizing either design enhances their effectiveness and reliability in various applications.

The other characteristics listed do not accurately represent the features of metal oxide surge arresters. While some surge arresters may have different voltage ratings, this is not a defining trait exclusive to MOSAs. They predominantly utilize resistive rather than capacitive components in their operation, and while MOSAs do have enhanced current-handling capabilities compared to older technologies, this is