If a series lc circuit has two inductors and one capacitor can it have more than one resonant frequency?
There will be only one resonance in a simulation where the inductors and capacitors are pure and ideal, with no parasitic capacitances or inductances. A more complete simulation model may show more resonances.If a series lc circuit has two inductors and one capacitor can it have more than one resonant frequency?
ωL = 1 / (ωC)
I would argue that your circuit is not the same as described by the OP, even in spirit. It is true that you have two inductors and at least one capacitor, but it is hardly a "series" circuit anymore. For each inductor there is a series path through the other inductor as well as a path around the other inductor. Also no complicated reactance models to get two points of intersection. Maybe the OP can comment on the practical application of such a network.Here is the result of a simulation of a practical series resonant circuit using two separate coils. Note the two series and two parallel resonances.
Clearly this situation can only occur in the presence of significant parasitic capacitances, but in the real world these do exist. Multiple resonances of this type can lead to unwanted effects, for instance in filter circuits.
Note that you don't need to get up to VHF to see this sort of thing: these resonances are occurring at quite low radio frequencies. The parasitic capacitances shown are large, but by no means impossibly so.
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Well, it's an attempt at a simple model model of two real inductors and a capacitor with parasitic elements. One could probably demonstrate something of the kind with actual components and an impedance / network analyser. There is no doubt that this kind of thing happens in practice: difficulties with spurious resonances have been with us since the days of great grandfather's TRF radio set. At higher frequencies this of course becomes more problematic, and eventually everything has to be regarded as more or less of a transmission line, but that's definitely heading OT.I would argue that your circuit is not the same as described by the OP, even in spirit. It is true that you have two inductors and at least one capacitor, but it is hardly a "series" circuit anymore. For each inductor there is a series path through the other inductor as well as a path around the other inductor. Also no complicated reactance models to get two points of intersection. Maybe the OP can comment on the practical application of such a network.
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