Mike said:
> "Because the 'XL' is really sq.rt (XL^2 + RL^2) and the 'XC' is really
> sq..rt (XC^2+ RC^2) where RL and RC are the series resistances of the
> inductor and capacitor respectively. If you take the case where Q=5, then the
> 'XL' becomes an impedance of 1.1XL with a phase angle of 78.7degrees, rather
> than 90"
Whoa Nellie! The way reactances are taught here are: XL) XL=2*Ï*f*L where
as Ï= 3.14 (for all practical purposes), f= frequency, and L= inductance in
henries. Then XL is the reactive component in ohms. XC= 1/2*Ï*f*C, where C=
capacitance in farads. Like wise, XC is the reactive component. <
Because the 'XL' is in inverted commas, I used it to refer to the 'XL' you
used in your equation. What I was pointing out is that in fact, the branch is
NOT just an inductive reacatnce of XL, but because of the resistance, has an
impedance and a phase angle that is not 90 degrees. So the branch you called
inductive 'XL' is actually an impedance of R+jXL , and I used 'XL' to mean that
particular branch to which you referred. So if you now calculate the frequency
at which the power factor is unity when the 'coil' branch of the parallel
circuit has an impedance of XL/5 + XL (i.e.a Q of 5), you'll see that it is
NOT where XL = XC.
Is this a bit clearer?
73
Peter G3RZP
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