[TCML] Terry Filter Resistors
mddeming at aol.com
mddeming at aol.com
Thu Jan 29 23:25:10 MST 2009
If there is no change in impedance over such a large range, it implies that L is identical to zero. I have a number of resistors which are wound with half the winding clockwise and half counterclockwise to minimize impedance problems. Possibly this is what you are seeing. As for the wide discrepancies between reported readings, I believe that the readings from any sophisticated instrument must be suspect unless you know exactly what assumptions are hard-wired into the device. Most folks never consider this.
From: Shaun Epp <scepp at shaw.ca>
To: tesla at pupman.com
Sent: Thu, 29 Jan 2009 7:03 pm
Subject: Re: [TCML] Terry Filter Resistors
I did some tests too with an LRC meter and the Terry filter resistors, I'm using
the 50 watt versions, Ohmite L50J1K0E so keep that in mind.
With a good Fluke meter (graphical 867b) the resistance reads 1.0214 Kohms
Compared to a Fluke 87 III they read 1.022 Kohms
Using my Tenma 72-960 LRC meter I can't get a stable inductance reading, but I
can measure ac resistance at two frequencies; 120 Hz and 1 Khz
I checked Rac at both frequencies and I read the same value - 1.021 Kohms
I looked in the manual and it doesn't say if it is impeadance or resistance that
is being measured, so I may have proved nothing.
Another check. -- I used the component tester feature on my Fluke 867b which
give you a V vs I graph of the component under test, and I can vary the
frequency from 2 Hz to 18.75 Khz. I connected the resistor to the meter and
tried it at different frequencies and there was no change in the slop of the
line; ie no change in impeadance between 2 Hz and 18.75 Khz.
That measurement of over 100mH that another coiler measured has got to be a
mistake (of the meter that is), this would require a large closely wound
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