The condition for which the impedance of a given electric, acoustic, or dynamic system is very high, approaching infinity. In an electric circuit consisting of a capacitor and a coil in parallel, antiresonance occurs when the alternating-current line voltage and the resultant current are in phase. Under these conditions the line current is very small because of the high impedance of the parallel circuit at antiresonance. The branch currents are almost equal in magnitude and opposite in phase.