What is the function of a varistor in electrical circuits?

A varistor's primary function within electrical circuits is to protect against voltage spikes. It does this by exhibiting a non-linear voltage-current characteristic, which allows it to absorb excess voltage when a spike occurs, thereby clamping the voltage to a safe level. This action helps to safeguard sensitive electronic components from damage caused by sudden increases in voltage, such as those that may arise from lightning strikes or power surges.

The reliability of varistors in absorbing transient voltage surges makes them an essential component in many electrical and electronic applications, enhancing the overall durability and safety of the systems they are installed in. Without varistors, electrical components could be exposed to harmful voltage levels, leading to failure or degradation over time.

While stabilizing voltage might relate to other components like voltage regulators, and options suggesting increasing current flow or converting AC to DC are functions associated with different electrical devices, these do not accurately describe the role of a varistor.