gyrator question (how does these two circuits be equal)

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liletian

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Hi Guys
In wikipedia gyrator, they use a amplifer to replace the gyrator. They claimed the attached circuit are equivilent.
First, I can not equal these two circuits.
Second, even they can equal, how does it relative to the gyrator idea? In other words, how can a op-am function as a gyrator? Normaly you use two for OTA with a capacitor to get inductance. I do not understand here how one op-am can replace four OTA.
Thanks a lot
 

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As I have often discovered: Don't blindly trust Wikipedia!
Both circuits don`t have the same input impedance.
For ideal opamp the input impedance is Z=(RL+sL)/(1+RL*sC).
An active realization of a grounded (ideal and lossfree) inductance uses two opamps or two OTA's.
 
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