What is the primary purpose of an electrical capacitor?

• A. To increase voltage
• B. To store electrical energy temporarily
• C. To measure electrical charge
• D. To decrease resistance in a circuit

Answer: (B)

The primary purpose of an electrical capacitor is to store electrical energy temporarily. Capacitors achieve this by accumulating electrical charge on their plates when a voltage is applied across them. This stored energy can be released back into the circuit when needed, allowing capacitors to play a vital role in various applications, such as smoothing out voltage fluctuations in power supply systems, providing timing functions in circuits, and filtering signals in audio and radio applications.

When a capacitor is charged, it holds energy in the form of an electric field between its plates. The capacity of a capacitor to store energy is determined by its capacitance, which is measured in farads. When the capacitor is discharged, this energy can be utilized by the circuit in various ways, making it a crucial component in electronic designs.

Other options describe functions that do not align with the primary role of a capacitor. Increasing voltage is typically the function of transformers or voltage regulators, while measuring electrical charge can be associated with devices like ammeters or specialized charge meters. Decreasing resistance in a circuit is related to conductors and resistors, not capacitors, as they primarily pertain to energy storage rather than controlling current flow in that manner.