HP 4262A Operating And Service Manual page 35

2) Influence on high capacitance and high in¬
ductance measurements.
When a high inductance (a high capacitance)
is measured, the residual factors in the test
jig also contribute a measurement error.
The affect of stray capacitance or residual
inductance on measurement parameters are:
Stray capacitance —*■ Offsets high inductance
measurements.
Residual inductance—►Offsets high capacitance
measurements.
These measurement errors increase in
proportional to the square of the test signal
frequency. The effects of the residual
factors can be expressed as follows:
p __Cx_
= 1 - <u2CxLres
or ( to2CxLres)
= 1 - o»2LxCst
or ( ^ n>2LxCst)
In a 10kHz measurement, for the measure¬
ment error to be less than 0.1%, the pro¬
duct of Cx and Lres (Lx and Cst) should be
less than 0.25 x lO'12. The relationship
between the residual factors of the test jig
and measurement accuracies are graphically
shown in Figure 3-4.
The 4262A ZERO ADJ controls cover the following
capacitance and inductance offset adjustment
ranges:
C ZERO ADJ: up to lOpF
L ZERO ADJ: up to lpH
An offset adjustment should always be performed
before measurements are taken.
3-XI