This is the circuit:
I saw it in a book. It said that this is a 7th order circuit.
From theory we know that the order of linear passive circuits is determined by the sum of capacitors and inductors, minus the number of Inductor-nodes (a node where only inductors meet), minus the number of capacitor-meshes (a mesh that has only capacitors on it's branches).
This is my attempt to verify the order.
Capacitors + Inductors = 11
That component to the leftmost part of the schematic, judging from the way the book is illustrated previously, is just a complex electric impedance, so I believe that we can't do anything with that component. It doesn't count neither as capacitor, or inductor. It may contain 10 inductors inside but that's irrelevant, in order to find the order of the circuit (I'm not sure about that though).
Far to the right (my rightmost arrow) the inductor and capacitor can change their place without the circuit being affected in any way, so we have an inductor node.
Another inductor node exactly to the left of the previous one.
And one capacitor mesh, that I have marked to the left.
Therefore the order is 11 – 2 inductor nodes – 1 capacitor mesh = 8, not 7. So I'm clearly missing something here and I have no idea what it is. The way this problem was presented in the book seemed more like a trick question.
I will appreciate any help on this! Thanks in advance!
Best Answer
You are missing the mesh/loop which includes the left-most capacitor, the upper capacitor and the right-most capacitor. 11 reactive components - 2 inductor nodes - 2 cap meshes = 7.
If you're feeling up to the challenge you can also attempt to find the transfer function of the circuit (s-domain). The circuit order is whatever is higher: the order of the numerator polynomial or the order of the denominator polynomial.