Gyrator, the fifth element

[Wytnucls]

Conceived in 1948, with several applications, one of which was to replace bulky inductors, the gyrator is rather mysterious.
Are they still used today? Could someone familiar with their use, care to explain how they work?

[IanB]

The Wikipedia article contains many details, does it not?

How they work:

A four terminal circuit element with a set of linear equations describing its behavior. The mathematical properties given by these equations can be simulated by a circuit built out of capacitors, resistors and op amps. In some sense this would be just like an analog computer.

Applications today:

As noted by the Wiki article, active circuits can simulate inductors and other components with apparent inductances much higher than a physical passive inductor could have of the same size. Applications are found in active filter circuits, for example.

[EEVblog]

The gyrator has been on FF video list for some time.
Yes, they are still used for filters and other stuff that would otherwise need really high physical inductance values.
They do actually work just like inductors, the only difference is there is (obviously) no ability to store energy in a magnetic field.

[Wytnucls]

The Wikipedia article is interesting but requires a vast knowledge of electronics to make any sense (2-port device, non reciprocal, network realization, isolators, circulators, current/voltage/impedance inverter), but doesn't explain how the device actually works.
http://en.wikipedia.org/wiki/Gyrator

I find this circuit animation of the gyrator more beneficial to the layman:
http://www.falstad.com/circuit/e-gyrator.html

Looking forward to Dave's take on the device, in a future video.

Here is a good write-up on the subject by Bryan Morrison and Thomas Lynch:
http://schematicsforfree.com/archive/file/Audio/Circuits/Filters/GYRATORS/Gyrator%20Theory.pdf