[Amps] Parasitics & Filament Sag

[R L Measures]

On Sep 3, 2006, at 6:39 AM, Peter Chadwick wrote:

> Rich said:
>
> > If an L-network was resonant on the operating frequency,  infinite
> current would flow through it because the reactive components are
> equal, opposite, in series, and not in parallel.<
>
> Only because of your non-rigorous definition of resonance.

XL = XC isn't rigorous enough on your side of the pond?

> AC theory tells us that the only definition of resonance that holds  
> for all cases is that the applied voltage and current are in phase.  
> The 'XL=XC' definition is a very loose approximation, and falls  
> over badly when Q is low. There are occasions where it doesn't  
> matter, but for an understanding of what is happening, it is  
> necessary to appreciate the inherent errors in the approximation.  
> The difference can be very important where feedback is applied,  
> because a tuning error can lead to instability.
>
> Ian says that in practice, it doesn't matter. Not to the  appliance  
> operator, I suppose.
>
> 73
>
> Peter G3RZP
>

R L MEASURES, AG6K. 805-386-3734
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