>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
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|