Editing Gyrator (section)

==== Comparison with actual inductors ====

Simulated elements are electronic circuits that imitate actual elements. Simulated elements cannot replace physical inductors in all the possible applications as they do not possess all the unique properties of physical inductors.

'''Magnitudes.''' In typical applications, both the inductance and the resistance of the gyrator are much greater than that of a physical inductor. Gyrators can be used to create inductors from the microhenry range up to the megahenry range. Physical inductors are typically limited to tens of henries, and have [[parasitic resistance|parasitic series resistances]] from hundreds of microhms through the low kilohm range. The parasitic resistance of a gyrator depends on the topology, but with the topology shown, series resistances will typically range from tens of ohms through hundreds of kilohms.

'''Quality.''' Physical capacitors are often much closer to "ideal capacitors" than physical inductors are to "ideal inductors". Because of this, a synthesized inductor realized with a gyrator and a capacitor may, for certain applications, be closer to an "ideal inductor" than any (practical) physical inductor can be. Thus, use of capacitors and gyrators may improve the quality of filter networks that would otherwise be built using inductors. Also, the [[Q factor]] of a synthesized inductor can be selected with ease.  The [[Q factor|Q]] of an LC filter can be either lower or higher than that of an actual LC filter&nbsp;– for the same frequency, the inductance is much higher, the capacitance much lower, but the resistance also higher. Gyrator inductors typically have higher accuracy than physical inductors, due to the lower cost of precision capacitors than inductors.

'''Energy storage.''' Simulated inductors do not have the inherent energy storing properties of the real inductors and this limits the possible power applications. The circuit cannot respond like a real inductor to sudden input changes (it does not produce a high-voltage [[Counter-electromotive force|back EMF]]); its voltage response is limited by the power supply. Since gyrators use active circuits, they only function as a gyrator within the power supply range of the active element. Hence gyrators are usually not very useful for situations requiring simulation of the 'flyback' property of inductors, where a large voltage spike is caused when current is interrupted. A gyrator's transient response is limited by the bandwidth of the active device in the circuit and by the power supply.

'''Externalities.''' Simulated inductors do not react to external magnetic fields and permeable materials the same way that real inductors do. They also don't create magnetic fields (and induce currents in external conductors) the same way that real inductors do. This limits their use in applications such as sensors, detectors and transducers.

'''Grounding.''' The fact that one side of the simulated inductor is grounded restricts the possible applications (real inductors are floating). This limitation may preclude its use in some low-pass and notch filters.<ref>{{Cite journal |last=Carter |first=Bruce |title=An audio circuit collection, Part 3 |date=July 2001 |id=SLYT134 |url=http://focus.tij.co.jp/jp/lit/an/slyt134/slyt134.pdf |journal=Analog Applications Journal |publisher=Texas Instruments }}. Carter page 1 states, "The fact that one side of the inductor is grounded precludes its use in low-pass and notch filters, leaving high-pass and band-pass filters as the only possible applications."</ref>  However the gyrator can be used in a floating configuration with another gyrator so long as the floating "grounds" are tied together.  This allows for a floating gyrator, but the inductance simulated across the input terminals of the gyrator pair must be cut in half for each gyrator to ensure that the desired inductance is met (the impedance of inductors in series adds together).  This is not typically done as it requires even more components than in a standard configuration and the resulting inductance is a result of two simulated inductors, each with half of the desired inductance.