4-4
Model 3550 LCR Meter Instruction Manual Operating Instructions
Measurement Tips cont’d:
Negative Capacitance or Inductance Readings
If a capacitor is connected to the 3550 while in the inductance measurement mode or if an
inductor is connected to the 3550 while in the capacitance mode, a negative sign will appear in the
display. The negative sign in the capacitance mode indicates an inductive measurement. The
negative sign in the inductance mode indicates a capacitive measurement.
If the resonant frequency of a DUT is reached, a “-“ sign will appear in the display.
Zero Correction of Parasitic Impedance
"Open Correction" is for the purpose of compensating for the stray capacitance and stray
conductance of cables or test fixtures. Executing an "Open Correction" procedure on the test
leads of fixture before measurement of high impedance DUTs improves measurement accuracy.
"Short Correction" compensates for the residual inductance and resistance of cables or test
fixtures. Performing a "Short Correction" procedure on cables or test fixture before measurement
of low impedance DUTs improves measurement accuracy.
If the condition or position of a cable or test fixture changes, you MUST carry out Zero Correction
to compensate for the change. When performing a Zero Correction, keep hands and metallic
objects away from the cable or fixture.
Table 4.2: Short and Open Null Connections
Open Correction Short Correction
Connection
Correct Incorrect Correct Incorrect
Terminal
Only
5-Terminal
Kelvin
Klips™
G L H
G L H G L H G L H
G L H
G L H G L H G L H
L
F
L
S
H
F
H
S
L
F
L
S
H
F
H
S
L
F
L
S
H
F
H
S
L
F
L
S
H
F
H
S
Insulator
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