How does an SMPS differ from a linear power supply?

The distinction between an SMPS (Switched-Mode Power Supply) and a linear power supply primarily revolves around their efficiency and voltage regulation capabilities. An SMPS is designed to convert the input voltage to a desired output voltage by switching the input on and off rapidly, which allows it to maintain a consistent output voltage across a broader range of input conditions.

Wider DC voltage regulation refers to the SMPS's ability to effectively manage variations in input voltage and output load without deviating significantly from the set output voltage. This is due to its high-frequency operation and regulation techniques that rapidly adjust to changes, providing better performance under varying conditions compared to a linear power supply, which often relies on the heat dissipation and the characteristics of linear components to regulate output, leading to more limited voltage regulation capabilities.

This performance aspect makes option B the most accurate characterization of the difference between these two power supply types, as an SMPS often excels in environments where efficiency and stability are essential.