Mr Al, If you analyze the circuit as posted on the Tutorial web page, with a zero-output impedance voltage source in parallel with R=60 Ohms, L=200mH, C=120uf there is no resonance. Ergo all discussion about current magnitude, bandwidth, resonant frequency on that Tutorial page can only apply if the circuit is reconfigured as I show in post #11....
And for the bandwidth they quote at 22 Hz, which is very close to the more accurate 22.1 Hz, but then when they go to calculate the upper and lower frequency they divide the bandwidth by 2 and then subtract and add to the resonant frequency of 32.5 and get a result that is a little more off than we might want to see...
What started this is that the OP took the circuit as drawn on the Tutorial page, put it into LTSpice and couldn't see any resonant behavior. No surprise! LTSpice nailed it! Now if the circuit had been drawn correctly in the first place, we wouldn't be having this discussion...
Oh, and btw: the reason that there can be no resonance with a pure voltage source connected across what would otherwise be a parallel tuned circuit, is that resonance depends on energy being transferred from the inductor to the capacitor and back again. If the voltage at the common node of the circuit is defined by the pure voltage source, then no energy can transfer.
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