GW Instek LCR-8101 (Replaced by LCR-8101G) User Manual
Page 35
GETTING
STARTED
35
Wire capacitance
When measuring the wire capacitance, the fixture
clips that are marked with H
F
(High Force)/H
S
(High Sense)
should always be connected to the
point that is influenced the most by noise.
Wire inductance
The wire inductance should be subtracted from
the measurement result.
5cm, 1mm diameter wire has 50nH inductance
5cm, 2mm diameter wire has 40nH inductance
Frequency factor
in inductor
measurement
When an inductor is measured at a frequency
much lower than that for which it is designed (for
example, an HF choke tested at AF), the inductor
tends to behave as an inductive resistor. In these
circumstances, measurement accuracy is widened
by (1 + 1/Q) where Q is the quality factor.
Air-cored coils
Air-cored coils can pick up noise very easily,
therefore they should be kept well clear of any test
equipment that may contain power transformers
or display scan circuitry. Also, keep the coils away
from metal objects which may modify inductor
characteristics.
Iron-cored and
ferrite inductor
The effective value of iron-cored and ferrite
inductors can vary widely with the magnetization
and test signal level. Measure them at the AC level
and frequency in use. When core materials are
damaged by excessive magnetization (for
example: tape heads and microphone
transformers), check that the test signal is
acceptable before connection.