Consider the two filter in picture
simulate this circuit – Schematic created using CircuitLab
Are the cutoff frequencies (i.e. the two frequencies at which $V_{out}=\frac{1}{\sqrt{2}} V_{in}$) the same for the two filters? (And therefore also the bandwidth is the same for the two filters?)
I think they should be the same since in both cases the condition $V_{out}=\frac{1}{\sqrt{2}} V_{in}$ reduces to
R2=(ωL−1ωC)2
Nevetheless it is strange that there is a frequency for which both $V_{out}$s taken at resistor and at LC series have the same value $\frac{1}{\sqrt{2}} V_{in}$.
Doesn't this violates Kirckoff voltage law? (At any time it should be $V_{in}=V_{R}+V_{LC\ series}$ but if $V_{R}=V_{LC\ series}=\frac{1}{\sqrt{2}} V_{in}$ then this is not true).
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