Analysis of this gyrator circuit (input impedance calculation)

mikeska

Joined Feb 18, 2009
7
Thanks! Right now I was trying to do the analysis for exactly the gyrator example shown on that website. I've found some threads talking about that type of gyrator on this forum, but I couldn't even follow the analysis.:eek:

SFG analysis looks like some sort of Alien technology to me :D I'll need to learn how to do it, it looks powerful..
But why use SFG analysis, and not simple Nodal/Mesh calculations? A couple of the SFG's i've looked at had a simplification step, so i guess that it's easier to solve once you get it set up. I'll have to spend some more time on google :)

Anyway, the "wikipedia" gyrator, and the one that the OP showed us are simpler to analyze than the implementation shown in the link.. at least that's what it looks like for me right now. I just hope that my approach wasn't horribly wrong.

~mikeska
 
Have a look at post #7 in this thread. The GIC circuit shown in the link:

http://mysite.du.edu/~etuttle/electron/elect66.htm

is topology A1A as shown in the image attached to post #7.

The circuit shown in the first post of this thread is topology B2D.

Interestingly, all those topologies have exactly the same input impedance if the opamps are ideal.

This thread:

http://forum.allaboutcircuits.com/showthread.php?t=15774

has an extended discussion of GIC's.

Here is explained the modern technique of analyzing circuits with the MNA method:

http://www.montagne.nl/analog-electronics/modified-nodal-analysis/modified-nodal-analysis.xhtml

Toward the bottom of that you'll find an analysis of the GIC.
 

mikeska

Joined Feb 18, 2009
7
That last link is GREAT ! That method is really nice, especially with the "stamps". I've got an exam next week, but I'll procrastinate by studying the Modified Nodal analysis. This is nice.. Do you think it would be possible to make a circuit simulator program build on top of the MNA? I wonder if that's how this one works..
http://www.falstad.com/circuit/e-amp-fullrect.html

Thanks again for the MNA link :D When did you learn about MNA?

~mikeska
 
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