Specifications

E-1
Appendix E: Q Measurement Accuracy Calculation
Q measurement accuracy for auto-balancing bridge type instruments is not specified directly as ±%.
Q accuracy should be calculated using the following equation giving the possible Q value tolerance.
Where, Qt is the possible Q value tolerance
Qm is measured Q value
ΔD is D measurement accuracy
For example, when the unknown device is measured by an instrument which has D measurement
accuracy of 0.001, and the displayed Q value is 200, the Q tolerance is calculated as:
This result means that the true Q value will be between 167 and 250.
Note: The following equation may be used to calculate the Q value tolerance. (The result is the same
at that from the above equation.)
Qt
Qm D
Qm D()
= ±
±
×
×
2
1
Δ
Δ
Qt =
±
=
1
1
200
0.001
1
0.005 ±0.001
Qt
Qm
D
=
±
1
1
D