Cathodic Protection Tester Practice Exam

Which current regularly reverses its direction of flow?

1. Direct current

2. Alternating current

3. Static current

4. High-frequency current

The correct answer is: Alternating current

Alternating current (AC) is characterized by the periodic reversal of its direction of flow. Unlike direct current (DC), which flows in a single direction consistently, AC alternates the direction of flow at regular intervals. This is a fundamental property of AC and is reflected in its waveform, typically sinusoidal, where the current and voltage vary cyclically. The ability of AC to change its direction is crucial for various applications, particularly in power generation and distribution. Most modern electrical systems utilize AC due to its efficient transmission over long distances and the ease with which voltage levels can be transformed using transformers. In contrast, direct current maintains a constant flow, static current refers to stationary electric charge, and high-frequency current typically describes alternating current at high frequencies, but still does not change the fundamental aspect of AC’s characteristic of reversing its flow direction. Therefore, the nature of alternating current makes it distinct and applicable in many electrical engineering contexts.