E. Measuring Resistance
(see figure 5)
Warning
To avoid damages to the Meter or to the devices
under test, disconnect circuit power and discharge
all the high-voltage capacitors before measuring
resistance.
To measure resistance, connect the Meter as follows:
1. Insert the red test lead into the
V
Ω
terminal and the
black test lead into the
COM
terminal.
2. Set the rotary switch to an appropriate measurement
position in
Ω
range.
3. Connect the test leads across with the object being
measured.
The measured value shows on the display.
Note
l
l
The test leads can add 0.1
Ω
to 0.3
Ω
of error to the
resistance measurement. To obtain precision readings
in low-resistance, that is the range of 200
Ω
, short-
circuit the red and black test leads beforehand and
record the reading obtained (called this reading as X).
Then use the equation:
measured resistance value (Y) – (X) = precision
readings of resistance.
For high resistance (>1M
Ω
), it is normal taking several
seconds to obtain a stable reading.
UT39C – At 20A Range:
For continuous measurement
10 seconds and interval not less than 15 minutes
When current measurement has been completed,
disconnect the connection between the testing leads
and the circuit under test.
l
l
( figure 5)
Black Red
14
Model UT39A/B/C: OPERATING MANUAL
