8
SRC-Tnetwork
8
Maintenance
4.3.3 Required Equipment
Many combinations of standards, transfer standards,
meters, and bridges may be used to calibrate this
instrument. The following are some possible choic-
es:
•
A dual source guarded bridge
•
A high-precision, high-stability digital multime-
ter (e.g. Fluke 8508A, Fluke 8588A or Keysight
3458A) or other DMM with an accuracy of 20
ppm or better for direct measurements.
4.3.4 Calibration Procedure
To calibrate an SRC-Tnetwork proceed as follows:
1. Set up the calibration equipment in the resis-
tance measurement mode.
2. Measure R1, R2 and R3. The bnc center
tap connection is there to assist in measur-
ing these resistances without opening the
standard. Just measure between the center
conductor of the bnc and the Source, Guard
and Output terminals.
3. Calculate the Eff ective R using the formula
in Figure 4.1
4.
Confi rm that the resistance is consistent with
historical measurements to verify stability.
Figure 4-1 Schematic and formulas
