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if an inductor has a parasitic resistance does it effect the resonance frequency, if so how?

Fo 1/2pi x sqr LC


No, it doesn't affect the resonant frequency but it does effect the circuit Q or quality factor. Q will effect the sharpness of the bandpass of circuits using the inductor and the losses(to heat) in the inductor. In general, the lower the resistance, the sharper the bandpass. To elaborate on the other poster's answer: For SERIES LC circuits( L and C in series) , the resonant frequency is not dependent on series resistance of L. For PARALLEL LC circuits (L and C in parallel) there is a small effect due to the series resistance of L. However, in practical circuits this effect is swamped by the tolerance in the components. By the same vein, capacitors exhibit leakage that can be modeled as a parallel resistance that will effect resonance. Inductors have parasitic capacitance that affects resonance. These effects are usually ignored by most EE's unless the currents or frequencies are very high since the component tolerances of 10%-50% or greater will swamp these effects. So, the answer they want on the exam depends on whether this is a high school, university or graduate school class. Talk to your teacher.
no. .
lets take a look at a parallel circuit and assumed R is the parasitic resistance in series with the inductor, what we got is RL//C fo [ 1/2pi ]{ sqrt[ (1/(LC) - (R / L)^2 ] } there is a (R / L)^2 that will affect the resonance frequency fo the construction of the coil ideally R should be minimized, the trick is how? assuming R 0 fo [ 1/2pi ]{ sqrt[ 1 / (LC) ] }
The Resistance of an inductor is not really called the parasitic resistance. It is called the intrinsic resistance. A parasitic element is an element that changes the intrinsic properties of the device by adding or subtracting from them (typically adding). A parasitic resistance of an inductor would be the solder resistance (which is usually small and negliable). The relationship of the Resistance to the Reactance of the inductor is known as the Q and is expressed as Q X / R, where X is the inductive reactance. The Q is also a definition of the -3dB bandwidth and determines the bandwidth from -3dB rolloff points from the center resonance frequency (fo). So where the resistance R is very small in relation to the Reactance X, the Q is high and the bandwidth is narrow (sharp Q). So where the resistance R is very large in relation to the Reactance X, the Q is low and the bandwidth is wide (flat Q).

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