Extech Instruments MA440 User Manual page 9

DC Current Measurements (MA445)
WARNING: Do not handle the meter above the finger/hand guard barrier.
CAUTION: Observe CAT III 600V with respect to Earth Ground for the Jaw.
CAUTION: Measure in the temperature range of 0 ~ 40
1. Rotate the function switch to the DC Current position .
2. The A and the DC symbols will appear on the display indicating DC Amperes (Amps). The
AUTO icon will also display indicating automatic ranging.
3. Zero any residual magnetism by pressing and holding the REL ZERO button with no
conductor in the jaws. See Fig. 3 and Fig. 4
4. Press the jaw trigger to open the clamp jaw. Position the clamp around only one
conductor. See Fig. 2 (previous section) for correct and incorrect clamping techniques.
5. Read the current in the display. The display will indicate the proper decimal point and
value.
NOTES:
To ensure maximum accuracy, place the conductor at the center of the clamp head, otherwise
additional error (± 1.0%) may apply.
If the readings are positive, the current is flowing in a downward direction (faceplate to back of
meter).
Do not release the trigger suddenly; the impact may lead to a change in readings since the Hall
element is sensitive not only to magnetism but also to heat and mechanical stress to some
extent.
DC
Fig. 3 – DCA Zero before measurement Fig. 4 – DCA Measurement
A
9
o
C only.
A
DC
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