UT3500 series
User Manual
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If you are testing with an alligator clip, you can use the test lead to directly clamp the
terminal of the DUT for four-terminal testing.
If you are testing with a crown probe test pen, you can put the red and black test lead
probes against the corresponding positive and negative terminals of the DUT for four-
terminal testing, as shown in Figure 3-3-2.
Figure 3-3-2 Schematic Diagram of Crown Probe Test Pen Measurement
Note: When a negative voltage appears, it is caused by the reverse connection of the
test leads, and the positions of the red and black test pen need to be changed.
3.4 Set Zero and Calibrate
Before testing, please perform the short circuit zeroing step to remove the stray resistance
and bias voltage caused by the test lead or external environmental factors.
The measured resistance value may
be very small, such as 3mΩ and 30mΩ range. When
the test current flows through the resistance, the voltage signal generated will be very weak,
and the maximum is only a few mV, so the position, length and shape of the test lead may
all have effects on the measurement. Therefore, the positions and conditions during setting
zero should be the same as those during subsequent measurement.
Note: In order to ensure the accuracy of the measured value during setting zero and
normal measurement process, the test pen or test lead must be kept away from any metal
parts, instruments running on electricity or other environments with magnetic fields.
3.4.1 Short-Circuit Test Leads
Before setting zero, please short-circuit the test clip as follows.
Correct Short Circuit Method of the Alligator Clip
1. Hold an alligator clip in each hand, and press the upper handle of each alligator clip at
the same time, so that the red and black alligator clips are opened as shown in Figure
3-4-1.
