What is the approximate magnitude of the impedance of a parallel R-L-C circuit at resonance?

In a parallel R-L-C circuit, resonance occurs when the inductive reactance and capacitive reactance cancel each other out, leading to maximum current flow through the circuit. At this point, the impedance of the circuit is significantly influenced by the resistance because the reactive components (inductance and capacitance) effectively cancel each other's effects.

At resonance, the impedance is predominantly determined by the resistive component of the circuit. Since the reactive components (inductive and capacitive) essentially balance each other, what remains is the resistance, which dictates how much current can flow due to an applied voltage across the circuit.

Thus, the magnitude of the impedance at resonance is approximately equal to the circuit resistance. This characteristic allows engineers and technicians to design circuits that can operate efficiently by utilizing this behavior, ensuring optimal performance at the desired frequency.