[AMPS] 2000 ARRL Handbook question

[measures]

>Rich says:
>
>>>There was no great difference between them at VHF, but at HF the 
>>>nichrome had much lower Q (as would be expected).
>>>
>>EUR  Tom --  your theory that the resistance of nickel-chromium alloys 
>>Increases with a decrease in frequency is not supported by any published 
>>measurement.  
>
>
>Rich, you've lost me here. To me Q is (in this context) XL/r. Let's have r
>constant with frequency; XL increases with frequency. Therefore the Q of an
>inductor rises as the frequency goes up, doesn't it? And falls as the 
>frequency
>(i.e. XL) goes down.
>
In this case we have a parallel resistance and a series resistance.  
Things are more compicated than they look.   I seems to me that you need 
to look at the measurements.  

>Now if the material has a permeability other than 1, resistance will rise 
>as the
>frequency goes up, but Q will still drop as frequency goes down. Isn't 
>this what
>Tom said?
>
Beats me.  I had trouble making sense out of it.  

>If you put a resistor across the nichrome inductor, then the value that Q can
>reach is limited, and the parallel impedance is, in the limit, the value of
>parallel resistance.
>
€  ¿?
>
>


-  Rich..., 805.386.3734, www.vcnet.com/measures.  
end


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