Four-Terminal Pair Configuration - Keysight E4980A User Manual

Measurement Procedure and Examples

Four-Terminal Pair Configuration

Four-Terminal Pair Configuration
Generally, any mutual inductance, interference of the test signals, or unwanted
residual factors in the connection method incidental to ordinary termination
methods will have a significant effect on measurement, especially at high
frequency. The E4980A/AL employs a four-terminal pair measurement
configuration that permits easy, stable, and accurate measurement while
avoiding the negative influences inherent in the above factors. The 4TP
configuration can improve the impedance measurement range to below 1 m
Figure 7-7
UNKNOWN terminals consists of four coaxial connectors.
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•
•
•
Figure 7-7 Four-terminal pair measurement principle
Figure 7-7
in the E4980A/AL
The four-terminal pair (4TP) configuration solves the effects of mutual coupling
between the leads by employing either or both of the following techniques. The
E4980A/AL employs the method 2. At frequencies higher than 10kHz, the
effects of 1. is also benefited on the E4980A/AL by the balun effects of the
coaxial test leads
1. The outer shield conductors work as the return path for the test signal
Keysight E4980A/AL Precision LCR Meter
shows the four-terminal pair measurement principle. The set of
HCUR: High current
HPOT: High potential
LPOT: Low potential
LCUR: Low current
Vx
Vx
*1 The shielding conductor of Lcur is shunted to the system ground
current (they are not grounded). The magnetic fields produced by the inner
and outer currents cancel each other because of the opposite directions
Ix
Ix
＊1
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