Why the Vout vs. VR graph looks like an oval loop?

Question

So we've performed an experiment about the resonance angular frequency and RLC circuits in the lab.
I understand that the phase of voltage on the inductor and the voltage on the capacitor are equal in magnitude but opposite in signs.
But this graph below also shows that the output voltage and the voltage on the resistor also creates an oval loop. I cannot get my head around on why it is like that.
Any help is appreciated.

The Photon · Answer

To get this result, presumably the R, L, and C elements are arranged in series. I'll assume that's the case in the rest of my answer.
Since the 3 elements are in series, the currents through them are the same at all times.
And, by Ohm's law, the resistor voltage is proportional to the resistor current. Therefore it's also proportional to the inductor current or the capacitor current.
Now, what do you know about the relationship between the current and voltage of an inductor?

Why the Vout vs. VR graph looks like an oval loop?

One Answer

Add your own answers!

Ask a Question