Electrical IBEW Practice Test 2026 - Free IBEW Practice Questions and Study Guide

The component that is used to store electrical energy for later use is the capacitor. Capacitors function by accumulating electrical charge when voltage is applied across their plates, and they can release this stored energy back into the circuit when needed.

This ability makes capacitors essential in various applications, such as in power supply smoothing, timing circuits, and frequency filtering. The energy stored in a capacitor is proportional to the voltage across its plates and its capacitance, described by the formula \(E = \frac{1}{2} C V^2\), where \(E\) is energy, \(C\) is capacitance, and \(V\) is voltage.

While transformers are crucial for stepping voltage levels up or down in alternating current (AC) systems and relays are used for switching and controlling circuits, they do not store energy in the same way that capacitors do. Resistors, on the other hand, dissipate energy as heat and are not designed for energy storage. Therefore, the capacitor is indeed the correct choice for the component that stores electrical energy for future use.