[Amps] Parasitics & Filament Sag

[Mike Sawyer]

Peter,
    Show me concrete evidence that the voltage and current are not in phase 
when XL=XC. Basic AC theory demonstrates that resonance is the point where 
all that's left is Z=R, where R is the DC resistance left in the circuit. 
Unless the formula has gone through a radical change since my classroom 
days, its always been Z= SQ.RT. R²+(XL-XC)², when at resonance = SQ.RT. R²= 
R. Now where am I going wrong here?
Mod-U-Lator,
Mike(y)
W3SLK

----- Original Message ----- 
From: "Peter Chadwick" <g3rzp at g3rzp.wanadoo.co.uk>
To: "R L Measures" <r at somis.org>; <g3rzp at g3rzp.wanadoo.co.uk>
Cc: <amps at contesting.com>
Sent: Monday, September 04, 2006 5:26 AM
Subject: Re: [Amps] Parasitics & Filament Sag


Rich said:
>XL = XC isn't rigorous enough on your side of the pond?<
It isn't on your side either, unless you're willing to accept an 
approximation that falls over completely for low Q in anything other than 
series circuits.
If you use the definition that resonance is where the volts and amps are in 
phase, you have a definition that holds for all cases, and you don't get 
this situation with low Q where XL doesn't equal XC. Basic AC theory.
As far as the PA tube is concerned, it wants to see a resistive load i.e. 
resonant by my definition.

73
Peter G3RZP
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