Continuity Measurements; Frequency Measurements - Extech Instruments MA440 User Manual

Continuity Measurements
WARNING: Please remove power to the circuit under test and discharge all capacitors
before taking resistance or continuity measurements. The meter will display OL if the circuit
under test is an open circuit of if the measurement exceeds the maximum range of the meter.
Do not input a voltage >30V AC or DC.
1. Turn the function switch to the Continuity
2. Use the M (mode) button to select the continuity display
3. Insert the black lead banana plug into the negative (COM) jack. Insert the red test lead
banana plug into the positive (Ω) jack. See Fig. 7 above.
4. Touch the test probe tips across the circuit or wire.
5. If the resistance is < 30Ω, the meter will beep. If the resistance is > 60Ω, the meter will
not beep. If the resistance is between 30 and 60Ω, the meter will stop beeping at an
unspecified point.
Frequency Measurements
WARNING: Do not input voltages > 30Vrms when measuring frequency.
Turn the function switch to the
1. Insert the black lead banana plug into the
negative (COM) jack. Insert the red test lead
banana plug into the positive jack. See Fig. 8.
2. Touch the test probe tips across the circuit or
component.
3. Read the Frequency measurement on the
meter display.
4. For the MA443 and MA445, use the M
(mode) button to view Duty Cycle %. For the
MA440 use the Hz% button to view Duty
Cycle %.
Hz%
position.
Fig. 8 – Frequency Measurements
12
position.
icon.
Hz %
AUTO
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