An example of a source of direct current is?

A car battery is an example of a source of direct current because it produces a constant voltage output in a single direction. This is a key characteristic of direct current (DC). Car batteries typically operate at 12 volts and are used to power electrical systems in vehicles, allowing for a steady flow of electricity that can power lights, radios, and starting mechanisms.

In contrast, options like a wall socket provide alternating current (AC), where the flow of electricity changes direction periodically. Solar panels, while they generate power through photovoltaic cells, initially produce direct current that can be converted to alternating current for household use, but they do not directly supply alternating current like a wall socket. Generators can produce either AC or DC depending on their design; however, many common generators produce AC as their output. Thus, a car battery distinctly fits the definition of a direct current source.