What is a transient wave of current in an electric circuit called?

A transient wave of current in an electric circuit is referred to as a surge. In electrical terms, a surge is a temporary increase in voltage or current that can occur in a circuit. This phenomenon can result from various factors, including lightning strikes, power outages, or the sudden switching on or off of machinery. Surges can potentially damage electronic components if protective measures are not in place.

The term "surge" specifically denotes a sustained increase in current that can last for several cycles, as opposed to a more abrupt and short-lived event, which could be referred to as a spike. Understanding these distinctions is crucial for designing effective lightning protection systems, as surges can compromise electrical equipment integrity.