Results Displayed - IET Labs, Inc. RLC Digibridge 1693 User And Service Manual

+ jX
θ
1
- j
δ
ω C
S
- jX
ESR for Capacitors. The total loss of a capacitor
can be expressed in several ways, including D and
''ESR'', which stands for "equivalent series resis-
tance" and which is designated ''Rs'' in the preceding
paragraph. To obtain ESR, be sure that the SERIES
indicator is lit; if you want ESR displayed simulta-
neously with C , push the [Cs/Rs] parameter key; if
you want the 5-place resolution for ESR, push the
[Rs/Q] key.
"Equivalent series resistance" is typically much larger
than the actual "ohmic" series resistance of the wire
leads and foils that are physically in series with the
heart of a capacitor, because ESR includes also the
effect of dielectric loss. ESR is related to D by the
formula
Parallel Equivalent Circuits for Inductors. Even
though it is customary to measure series inductance
of inductors, there are situations in which the paral-
lel equivalent circuit better represents the physical
device. For small "air-core" inductors, the significant
loss mechanism is usually "ohmic" or "copper loss"
in the wire; and the series circuit is appropriate.
Operation
+ jX
R
S
+ R
j ω Ls
δ
θ
Z R
S
- jX
R R
S S
C L
S S
IMPEDANCE
Figure 3-28: Phase relationships
+ jB
Z Y
1
j ω Cp
- j
ω L
δ
θ
+ R + G
G
P
- jB
C R
P P
or
G
P
ADMITTANCE
However, if there is an iron core, the significant loss
mechanism may be "core loss" (caused by eddy
currents and hysteresis); and the parallel equivalent
circuit is appropriate, being a better model of the
inductor. Whether this is true at any particular fre-
quency should be determined by an understanding of
the DUT, but probably it is so if the following is true:
that measurements of Lp at two frequencies near the
frequency of interest differ from each other less than
do measurements of Ls at the same two frequencies.

3.3.3 Results Displayed

3.3.3.1 Principal Measurement
Results
The principal Digibridge measurement will be pre-
sented on the left (RLCGZY) part of the display panel
in one of four ways; VALUE, deltaRLC, delta%, or
BIN No., (only one way for any single measurement).
VALUE, Selected by the [DISPLAY] Key. This mea-
surement provides two displays: the principal one is
R, L, C, G, Z or Y and the secondary one is Q, D, R,
X, B or DEG. The VALUE selection is the power-up
1693 RLC Digibridge
+ jB
G
P
+ G
θ
δ
P
Y
- jB
L R
P P
or
G
P
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