A grounded inductor is proposed which contains only one resistor and operational amplifier. The circuit uses the inherent frequency dependent characteristic of an amplifier to simulate the inductor. A parallel resonance circuit is constructed with the proposed circuit. It has been proved by the experimental results of the resonant circuit that the proposed circuit is equivalent to the grounded lossy inductor. The lossy inductor is imbedded in a passive bandstop prototype, and the resultant characteristic curve has been verified by the experiment.