Electronic – time constant confusion of second order system

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For first order systems, its easy to get the time constant by using thevenin concept.

Suppose i have a second order system ,for example consider a two stage cascaded LOW PASS FILTER with identical resistance and capacitor values.

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I am sure that this system will have more than 1 time constant.

However,

My guess is that the transfer function of desired output with respect to input voltage will have 2 poles and the reciprocal of these poles will give the time constants.

I am confused whether depending on the output of interest, will the poles change, i think it won't but i am not able to convince myself.

Best Answer

The poles of a system do not depend on the selected output node and, more than that, the also do not depend on the selected input node - as long as you select a node that was at ground potential before.