Store energy in an electric field and is used in timing circuits and filters?

• A. Inductor
• B. Resistor
• C. Capacitor
• D. Transformer

Answer: (C)

Capacitors store energy in an electric field between their plates. When voltage is applied, charge builds up on the plates, and the stored energy is given by E = 1/2 C V^2. This ability to charge and discharge at controlled rates makes capacitors ideal for timing circuits—the time it takes to charge or discharge through surrounding components (like a resistor) sets a timing interval via the RC time constant. In filters, the capacitor’s impedance is 1/(ωC), so it reacts differently at various frequencies; together with resistors, it forms networks that pass or reject certain frequency ranges, shaping the signal. Energy storage in the electric field and the resulting frequency-dependent behavior explain why this component is used in both timing and filtering applications. Inductors store energy in magnetic fields and are common in other tuning/filter contexts, while resistors and transformers don’t provide the same energy-storage behavior.