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In article ,
wrote:

On 12 Jun 2005 16:59:08 -0700, wrote:

To properly use an LCR meter, I believe the following would be
appropriate.

1) Realize the meter measures total impedance and computes inductance
using the impedance figure in the place of reactance. (I read this on a
web page)
2) Measure the inductance and resistance, or capacitance and
resistance.
3) Find the impedance associated with the inductance, using the meter's
test frequency.
4) Recombine the impedance and resistance to find the reactance using
Pythagoras.
5) Once again using the meter's test frequency, find the new inductance
or capacitance associated with the reactance.

Right? Assuming the real component is strictly L-R or R-C.

Doug

Most LCR meters are pretty crude devices and simply indicate
the scalar impedance of the test device. However the dial calibration
is based on the assumption that the test device is a pure lossless L
or C.

The only ~$200 handheld LCR meter that doesn't make the assumption of
lossless (pure) inductance or capacitance that I know of is the Extech
model 380193 LCR Meter. I have one, and it works well. It measures L,
C, or R at 120 Hz or 1000 Hz (but not R at DC), and for L and C also
reports parasitic R.

The B+K model 875B LCR meter did not work for me because they only
worked with very pure inductances. I have heard that the Wavetek meters
also have the problem. The test is to take a relatively pure
inductance, like one winding of a power transformer, and put a
potentiometer in series. Does the reported inductance vary as the
series resistance is increased? With the B+K, it just explodes, with
the indicated inductance becoming a large factor bigger than the true
value, so a 2-henry inductor was reported as 45 henries. Complete
nonsense, rendering the meter useless.

Note that one-frequency and two-frequency LCR meters cannot detect
self-capacitance in an inductor, or self-inductance in a capacitor.
Only parasitic resistance can be detected.

Joe Gwinn