In general, the impedance of a circuit is partly resistive and partly reactive. The real part is the resistance, and the imaginary part is the reactance. The reciprocal of the impedance Z is the adm...In general, the impedance of a circuit is partly resistive and partly reactive. The real part is the resistance, and the imaginary part is the reactance. The reciprocal of the impedance Z is the admittance, Y .