Washington Esthetician State Board Practice Exam

A battery is a classic example of a direct current (DC) source because it provides a steady flow of electric charge in one direction, which is the defining characteristic of direct current. In a battery, chemical reactions occur that produce a constant voltage, allowing it to power devices directly without requiring any conversion.

In contrast, a wall socket typically supplies alternating current (AC), which changes direction periodically. Generators can produce either AC or DC, depending on their design, but are more commonly associated with generating AC power for widespread electricity distribution. Solar panels can produce DC as well, but they usually require an inverter to convert that DC into AC for household use. Therefore, the battery remains the clearest example of a direct current source.