[TCML] Terry Filter Resistors
piranha at drsstc.com
Thu Jan 29 21:16:19 MST 2009
Better LCR meters read "Q" at 1000 Hz. 50mH at 1000Hz is .314 ohms.
Sort of hard to see with 1000 ohms in series... Your going to have to
pump MHz through there to see the inductive effects... The 27XT is a
wonderful meter and I use mine almost every day :D But it is designed
to measure the inductance of grandma's old tube TV's inductors, not
I have the digital signal generators and all if some "experiment" needs
to be done. Time is short these days, but if a question needs an
answer, I will make it so...
> Hi Ed, Gary,
> WOW! I think your right. That sure puts a damper on my multi-layer
> technique! Would work in multilayer mode, but if a 1K 1/2W carbon is
> measuring 184mH, then yes, all bets are off and a good lesson learned
> with the 27XT (and maybe any LCR).
> Excellent test Gary!
> Take care,
> Ed Phillips wrote:
>> I also have a 27XT multimeter. If I take a 1.0K Ohm, 1/2W carbon
>> comp resistor (i.e. NO significant inductance) and try to measure its
>> inductance with this meter, it reads 184mH. I don't think so!
>> Bottom line - don't try to measure inductance of resistors with this
>> Regards, Gary Lau
>> MA, USA"
>> Measuring any kind of coil with this type of meter is sort of a
>> gamble unless you know what you're doing - the measurement technique
>> is quite an indirect one. Works OK with reasonable coil Q but not at
>> all suitable for measuring the inductance of a WW resistor. To do
>> that I'd break one and try to figure out the number of turns and then
>> calculate it. I don't think even a good impedance bridge would give
>> useful results.
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