Thursday, March 05, 2015

Intuitively Please : R1C1 Into R2C2

Intuitively, say what the bode plot should be. That part's not hard - you can work from what you'll get at f=0 and f=0 (what do caps do at both extremes?)

But, can you intuitively say what the pole and zero are? The math is easy, you could do this in a minute.. but.. think..

You already have a Thevenin circuit - so, if you make a Norton equivalent, what current do you get? And into what load? Get it - the load is everything in parallel - so, since that load looks like a short at infinite freq, obviously you have a pole at W = 1/(R1||R2 (C1 + C2)) . Easy.

Zero? What current do you get in your Norton equivalent? You have a part through an R and a C - at high frequency, it goes up because of the cap - so, obviously a pole - and, the frequency has to be W = 1/ (R1 C1). Childishly simple..


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