Utah Master Esthetician Practice Exam

Which type of current flows in only one direction?

1. Alternating Current

2. Direct Current

3. Residual Current

4. Pulsating Current

The correct answer is: Direct Current

The correct response is Direct Current, which is characterized by the flow of electric charge in a constant direction. This unidirectional flow means that, unlike Alternating Current, which reverses direction periodically, Direct Current maintains a steady polarity. In practical terms, Direct Current is commonly used in battery-operated devices and low-voltage applications, making it ideal for electronic circuits where stable voltage is crucial. Understanding this distinction is important for estheticians, particularly when working with equipment that uses electricity, such as facial machines or LED therapy devices, which often rely on Direct Current for their operation. Alternating Current, on the other hand, fluctuates in polarity and changes direction, which is unsuitable for many direct use applications seen in esthetics. Residual Current refers to the leakage of current that can occur in a circuit, like in the case of Residual Current Devices (RCDs) that prevent electric shocks. Pulsating Current varies in magnitude and can still change direction, further distinguishing it from the steady, consistent flow found in Direct Current.