Errors In High Resistance Measurements; Offset Compensation - DATATEC EDU34450A Guia Del Usuario

Range
100 Ω
1 kΩ
10 kΩ
100 kΩ
1 MΩ
10 MΩ
100 MΩ

Errors in High Resistance Measurements

When you are measuring large resistances, significant errors can occur due to resistance insulation and surface
cleanliness. You should take the necessary precautions to maintain a "clean" high-resistance system. Test leads and
fixtures are susceptible to leakage due to moisture absorption in insulating materials and "dirty" surface films. Nylon
and PVC are relatively poor insulators (10
Leakage from nylon or PVC insulators can easily contribute a 0.1% error when measuring a 1 MΩ resistance in humid
conditions.

Offset Compensation

A resistance measurement involves measuring a voltage (E) induced across the resistance by a known current
source.
Thermal EMF caused by dissimilar metals can create a parasitic voltage in the measurement circuit (V
thermal EMF can be caused by the input lead connections or internally in resistor R. In general, this voltage will not
change with the current applied to the resistor.
104
Test Current DUT Power at Full Scale
1 mA
0.5 mA
100 µA
10 µA
1 µA
100 nA
100 nA/10 MΩ
9
Ω) when compared to PTFE insulators (10
100 µW
250 µW
100 µW
10 µW
1 µW
100 nW
1 µW
Keysight EDU34450A User's Guide
13
Ω).
). The
EMF