User manual

Clamp Meter Features 3
Making Relative Measurements (Null)
U1190A Series User’s Guide 57
Making Relative Measurements (Null)
When making Null measurements, also called relative, each
reading is the difference between a stored (measured) null
value and the input signal.
One possible application is to increase the accuracy of a
resistance measurement by nulling the test lead resistance.
Nulling the leads is also particularly important prior to
making capacitance measurements.
1 To activate the relative mode, press the key. The
measurement value at the time, when Null is enabled, is
stored as the reference value.
Figure 3-4 Null display
2 To disable the Null function, press again.
For any measurement function, you can directly measure and
store the null value by pressing with the test leads open
(nulls the test lead capacitance), shorted (nulls the test lead
resistance), or across a desired null value circuit.
NOTE
• In resistance measurement, the clamp meter will read a non-zero value
even when the two test leads are in direct contact because of the
resistance of these leads. Use the Null function to zero-adjust the
display.
• For DC voltage measurements, the thermal effect will influence the
accuracy of the measurements. Short the test leads and press
when the displayed value is stable to zero-adjust the display.
U119XA UG.book Page 57 Thursday, September 15, 2011 4:03 PM