On Wed, 01 Dec 2004 19:57:48 -0800, Roy Lewallen wrote:

budgie wrote:

On Wed, 01 Dec 2004 16:35:36 -0800, Roy Lewallen wrote:


Duncan Munro wrote:

The kind of measurement frequencies we are talking about are in the order
of 700kHz. At that frequency, the inductance of the 'indicated' 4.5uH is
19.8 ohms, not a million miles from the 22 ohms of the resistor itself -
this is not what I would call a reasonable 'Q' value. Fair play to AADE,
it's designed to measure the inductance of inductors, not other components
;-)

If the reactance is much lower than the resistance, it's generally
inconsequential in a practical application. I think that's almost always
the case for carbon film resistors, and I suspect it's nearly always the
case for metal film resistors.

Probably, if the Q is so low as to make measurement difficult, it's
probably low enough that the X isn't important in a practical application.


(adds) ..... at the test frequency

Sure. Any statement about a frequency-dependent property like X or Q
applies only at the frequency at which the component has that particular
X or Q.

I only added that because the test frequency was cited as ~700kHz and a casual
reader may have taken the above to mean that the X was insignificant at the
frequency of intended operation.