At resonance, what impedance does a parallel tuned circuit exhibit?

In a parallel tuned circuit (often called a tank circuit), an inductor and a capacitor are connected in parallel. At resonance, the inductive reactance and capacitive reactance are exactly equal and opposite. Because they are equal, the currents circulating between the inductor and capacitor effectively cancel out the overall current drawn from the external AC source. This results in very little current flowing from the source into the parallel circuit, which mathematically means the circuit presents a very high impedance. This is the exact opposite of a series tuned circuit, which exhibits its lowest impedance at resonance. Remembering this distinction is crucial for understanding how different filters and amplifier circuits are designed.