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5.4 Resistance Measurement
Attention!
Make sure all objects, circuits and components under test are without
voltage!
Set the rotary function switch to resistance measurement (
/Ohm ). If
the annunciator for continuity test “M
Ω
“ is displayed, press DC Ohm/
AC (
) button until the symbol disappears.
Now connect the test-lead to the device you want to measure. Make sure
all power is removed. Auto Range always selects the appropriate range,
to avoid reading mistakes.
Normally the resistance of the test-leads can be disregarded (approx. 0.1
to 0.2 Ohm). But even this small value can cause inaccuracy in the 400 Ohm
range. To determine the error before measurement short the test-lead
tips together and read the resistance value in the display, this value must
be deducted from the display reading.
During resistance test, make sure that the contact between probes and
circuit is good. Make sure the test points are free of dirt, oil or solder flux
or similar, etc. This might seriously influence the measuring result.
If resistance over 4 MOhm is measured, the display might need a few
seconds to stabilize.
If the measured resistance value exceeds the range “OL“ appears in the
display or the line is interrupted/high-ohmic (> 40 MOhm)
Hint!
During resistance measurement the three sub-displays below the main-
display are active. In the left sub-display the present reading is taken
1 second later, the middle display the reading is taken 2 seconds later
and in the right display the reading appears 3 seconds later.
This means the left sub-display shows the measurement value which was
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to the object to be measured. If the line resistance is less than 40 Ohm
a test buzzer sound is emitted.
Attention!
Never measure capacitors which carry voltage, as a possible discharge
could destroy your measuring unit.
Hint!
During continuity check the three sub-displays below the main-display
are active. In the left sub-display the present reading is taken 1 second
later, the middle display the reading is taken 2 seconds later and in the
right display the reading appears 3 seconds later. This means the left sub-
display shows the measurement value which was 1 second earlier on the
main display, the middle sub-display shows the reading which was 2 seconds
earlier in the main display and the right sub-display shows the value which
was 3 seconds earlier in the main-display.
