GW Instek LCR-800 Series User Manual page 17

LCR-800 Series User Manual
Unless for special reason, always select "Series" for capacitors and inductors.
This has traditionally been standard practice. For very small capacitance or
inductance, select a higher test frequency for better accuracy. For very large
capacitance or inductance, select a lower test frequency for better accuracy. For
dc resistance, select a lower test frequency to minimize ac effects.
Because the reactive component most likely to be represented in a low resistance
resistor is series inductance, the "Series" is selected for a resistor below about
1kΩ. If a resistor large than 10MΩ, select "Parallel" that because the reactive
component most likely to be represent in a high resistance resistor is shunt
capacitance. If the Q is less than 0.1, the measured Rp is probably very close to
the dc resistance.
The total loss of a capacitor can be expressed in several ways, including D and
"ESR" (Equivalent Series Resistance). "ESR" is typically much larger than
actual "ohmic" series resistance of the wire leads and foils that are in series with
the heart of a capacitor physically, because ESR includes also the effect of
dielectric loss. ESR is related to D by the formula: ESR = Rs = D/ωCs. Where ω
represents "omega" = 2 pi time frequency.
Although it is traditional to measure series inductance of inductors, there are
situations in which the parallel equivalent circuit better represents the physical
component. For small "air-core" inductors, the significant loss mechanism is
usually "ohmic" or "copper loss" in the wire, therefore the series circuit is
appropriate. Nevertheless, for an "iron core", the significant loss mechanism can
be "core loss", therefore, the parallel equivalent circuit is appropriate which
being a better model of the inductor.
L 1.2345H
Q 0.6789
F : 1.000 kHz
V : 1.000 V
AUTO MANU
Figure 4-4. Selections of Series & Parallel Circuit
4-4-3. Measurement Displays
TESTING
R.H OFF
C.V OFF
INT.B OFF
13
SPEED
SLOW
DISPLAY
VALUE
MODE
L/Q
CIRCUIT
SERIES
MENU
Press F4 key to
select the Series
or Parallel circuit