Which of the following is an application for a capacitor in electrical systems?

The application of capacitors for power factor correction is essential in electrical systems, particularly when dealing with inductive loads. Capacitors help to improve the power factor by offsetting the lagging current produced by these loads, such as motors and transformers. By adding capacitors to the electrical system, the overall power factor is adjusted closer to unity, which reduces reactive power and can lead to more efficient power usage. This not only decreases electricity costs but also minimizes losses in the electrical distribution system.

In contrast, while controlling voltage spikes is an important function in some devices, it is typically achieved with other components such as surge protectors or voltage clamping devices rather than relying solely on capacitors. Converting AC to DC is a task achieved with rectifiers rather than capacitors, even though capacitors play a supportive role in smoothing out the output after conversion. Grounding electrical circuits is a safety measure primarily managed through specific grounding systems and conductors, which does not directly involve the function of capacitors. Thus, the role of capacitors in power factor correction is the most relevant application in this context.