Keysight Truevolt Series Operating And Service Manual page 67

Features and Functions
Negative Resistance Measurements
Under certain conditions, the instrument may report negative resistance measurements. These may occur
in 2-wire and 4-wire resistance measurements or continuity measurements.
Conditions that may cause negative ohms values include:
Changes in Front/Rear switch contact resistance
l
Reversed Sense Hi and Lo leads
l
Circuits with external bias or thermal voltages at circuit connections
l
Changes in measurement connection after a NULL operation
l
Under the same conditions, the 34401A returns the measurement's absolute value so as to prevent the
confusion associated with negative readings. The Keysight True volt Series DMMs will return negative val-
ues. This allows the most accurate results after a NULL operation.
68 Keysight True volt Series Operating and Service Guide