To reduce the pitting of relay contacts that make and break frequently, what unit is generally connected across them?

To mitigate the pitting of relay contacts that frequently make and break, a capacitor is commonly connected across them. This practice is grounded in the behavior of electrical circuits, where a capacitor helps dampen voltage spikes that occur during the making and breaking of contacts.

When the relay contacts close, the sudden inrush of current can create significant arcing, which contributes to contact pitting and wear. By placing a capacitor across the contacts, it acts as a buffer, absorbing the energy from these spikes and minimizing the electrical stress on the contacts. This significantly increases the lifespan of the relay by reducing wear and tear.

In contrast, while other components like a resistor or transformer might serve various roles in electrical circuits, they do not sufficiently address the issue of contact erosion caused by rapid switching. A switch, while it may seem relevant as a device that also makes and breaks connections, does not play a protective role in this context. Thus, using a capacitor is the most effective method to protect relay contacts from damage due to electrical arcing.