gyrator question (how does these two circuits be equal)
时间：04-07
整理：3721RD
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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
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
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.
In general, the input impedance of the two circuits is not the same. However under some hypothesis they can be very similar, so you can use the op-amp circuit to simulate an inductor in a limited frequency range. Please refer to http://www.eecs.berkeley.edu/Pubs/Te...CS-2009-20.pdf