What two components are required to form a tuned circuit?

A tuned circuit, commonly known as an LC circuit or tank circuit, requires two fundamental components: an inductor (coil) and a capacitor. These two components work together to store and exchange electrical energy, creating electrical resonance. The capacitor stores energy in an electric field, while the inductor stores energy in a magnetic field. When connected together, energy oscillates back and forth between the two components at a specific natural frequency determined by their values. Resistors are not required to form a tuned circuit; in fact, they dissipate energy and lower the efficiency (the Q factor) of the resonance. Transistors and diodes are active or non-linear components used for amplification or switching, not for establishing a fundamental resonant frequency.