[ARC5] LCR meter - question in support of mil surplus restoration....

[Dennis Monticelli]

Most LCR meters we can afford use a low freq for the measurement.  This
means that the reading may be way off if a magnetic core is involved.  If
you don't mind the size, look for an old Q meter.  That will measure at the
desired freq and tell you the quality factor.   As for the cheap handheld
stuff, I would not trust them for RF purposes unless the component is flat
with freq.  An exception is the Autek Research RF Analyst.  I have the old
version, RF-1, and makes its measurements at the chosen freq.  It is also
very small.

Dennis AE6C


On Thu, Nov 21, 2013 at 7:53 PM, Roy Morgan <k1lky68 at gmail.com> wrote:

>
> On Nov 21, 2013, at 9:43 PM, John Hutchins <jphutch60bj at gmail.com> wrote:
>
> > Group -
> >
> > I have a question -  Al the LC|LCR meters ... are > 100.00 but oll onl
> measure down to 20uH  3 digit precession or 200UH 5 digit precession….  one
> ...on Ebay ... goes to : 0.001uH
> > Any thoughts ?
>
> Yes.
> Here are my thoughts:
>
>  - NO one doing ham work *needs* three digit precision, let alone 5 digit
> precision (except in frequency setting)
>
>  - The results you get from measuring an inductor to three digits would
> almost certainly change by at least one digit in the second place and who
> knows what in the third place, simply by making the leads a bit longer or
> shorter when testing.
>
>  - 20 micro henries is not a lot of Henry.  RF coils in transmitters might
> be of this magnitude.  It may be far more realistic and meaningful to put a
> test coil into a real circuit and measure it’s resonant frequency with a
> good grid dip meter.
>
>  - The meter that can measure down to 0.001 micro henry is almost
> certainly fooling both itself and you with such numbers. One inch of number
> 14 wire has an inductance of 0.016 micro henry (see:
> http://www.consultrsr.com/resources/eis/induct5.htm )
>
>  - There is an important difference between precision and accuracy.  Do
> not confuse the two.  How space scientists and engineers can hurl a one-ton
> thing off to Mars and have it arrive a year later at JUST the right place
> and velocity boggles my mind.  I suspect they have developed an
> unprecedented amount of both precision and accuracy.  (And considerable
> patience.)
>
> Side note:
> The first day of Hanukkah falls on Thanksgiving this year.
> It will not do so again for some seventy eight thousand years.  Who knew?
>  (*)
>
> Roy
>
> Roy Morgan
> RoyMorgan at alum.mit.edu
> K1LKY Since 1958
>
> *  Jonathan Mizrahi, a Jewish-American quantum physicist at Sandia
> National Laboratories in Albuquerque tells us this.
> Some learned people tell me that I, and you, might be back here for that
> event.  Email me off list for more.
> ---------
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