In an RLC circuit, which components are present?

• A. Resistor, Inductor, and Capacitor.
• B. Resistor and Inductor only.
• C. Capacitor and Inductor only.
• D. Transformer and resistor.

Answer: (A)

An RLC circuit includes resistor, inductor, and capacitor. That trio is what the name implies: the circuit is built from all three fundamental passive elements that store or dissipate energy. The resistor dissipates energy as heat and sets how quickly the circuit damps, the inductor stores magnetic energy and presents an inductive reactance that rises with frequency, and the capacitor stores electric energy with a capacitive reactance that falls as frequency increases. Together they define the overall impedance across frequencies and can produce resonance when the inductive and capacitive effects balance. If one component is missing, you no longer have an RLC circuit—the circuit becomes either an RL or an LC configuration, so to be an RLC circuit all three elements must be present.