Bandwidth of a parallel resonant circuit?
My task is to determine/display the bandwidth of a parallel resonant circuit in LTspice. As I understand it, the bandwidth of a parallel resonant circuit refers to the impedance and/or voltage across the capacitor and inductor.
Theoretically I would have a bandwidth of 2.34 kHz using the formula 1/(2pi*R*C).
In LTspice, however, I get about 8.6 kHz graphically.
Can someone explain to me where this discrepancy comes from?
Thanks in advance 🙂
(No Ratings Yet)
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I don’t understand the simulation result. In response, the resistance of the parallel circuit, which is ideal here, becomes infinitely large and no current can flow.
Can it be that your simulation program automatically adds a loss resistance to L and/or C?
For the ideal L-C circuit, the bandwidth is zero (infinitely large resistance).
Question: Why does the resistance shown consist of 2 parts? What does that mean? Or is the sketch incorrect and the resistor Rs is only parallel to the coil?
I know the formula you call here for the parallel resonant circuit only if the resistance is parallel to the resonant circuit and not in series with this.
Do you know how to get the formula for bandwidth in this case?
In the case, I think you’d have to do this myself.
This is possible, for example, by recreating it with the Laplace transformation.
The paralle circuit of L and C would have the impedance sL/(LCs2+1)
In series with R, the total impedance is Z=R+sL/(LCs2+1)
You can now evaluate this directly or replace s with jw and direct the two 3dB limit frequencies directly.