I was trying out various gyrator topologies, emulated and for real and stumbled across one I don't think I've seen before:

It looks like a NIC stacked on top of a NIC, but note the opamp input polarities are inverted from the normal. (The choice of opamp for emulation is arbitrary by the way, I used a NE5532 for the physical realization)

This sort of makes sense as this guarantees high frequency feedback is negative and thus stability. It does emulate and work for real. Changing the capacitors for resistors will destabilize this topology so its only suitable for a FDNR, not a grounded inductor.

But there's another catch.

Although its basically stable it can misbehave, and does so in real life - thought I'd leave this for people to muse over and figure it out.

[I should add that this is not intended to be voltage driven, the real life circuit has a source with an impedance of several kohms]

It looks like a NIC stacked on top of a NIC, but note the opamp input polarities are inverted from the normal. (The choice of opamp for emulation is arbitrary by the way, I used a NE5532 for the physical realization)

This sort of makes sense as this guarantees high frequency feedback is negative and thus stability. It does emulate and work for real. Changing the capacitors for resistors will destabilize this topology so its only suitable for a FDNR, not a grounded inductor.

But there's another catch.

Although its basically stable it can misbehave, and does so in real life - thought I'd leave this for people to muse over and figure it out.

[I should add that this is not intended to be voltage driven, the real life circuit has a source with an impedance of several kohms]

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