[Amps] *** SPAM *** Re: Parasitics & Filament Sag

[Peter Chadwick]

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*π*f*L where as π= 3.14 (for all practical purposes), f= frequency, and L= inductance in henries. Then XL is the reactive component in ohms. XC= 1/2*π*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