A steady state electrical current is defined as DC, while a periodic current that alternates is referred to as AC. A single-polarity pulse of rising current, such as a rectified sine wave, is classified as a DC pulse, though it requires additional details like rise time and duration for clarity. The term DC can be misleading if used to describe unidirectional currents that vary in amplitude, as this can lead to confusion with AC terminology. To avoid ambiguity, it's recommended to clearly differentiate between pure DC and varying currents, which may exhibit characteristics of both AC and DC. Understanding these distinctions is crucial for accurate communication in electrical discussions.