Extech Instruments MN47 User manual

User's Guide
Autoranging Multimeter
Model MN47

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Introduction
Congratulations on your purchase of the MN47 MultiMeter. The MN47 offers AC/DC Voltage, AC/DC
Current, Resistance, Diode, and Continuity and Temperature. Proper use and care of this meter will
provide many years of reliable service.
Safety
This symbol adjacent to another symbol, terminal or operating device indicates
that the operator must refer to an explanation in the Operating Instructions to
avoid personal injury or damage to the meter.
This WARNING symbol indicates a potentially hazardous situation, which if not
avoided, could result in death or serious injury.
This CAUTION symbol indicates a potentially hazardous situation, which if not
avoided, may result damage to the product.
This symbol advises the user that the terminal(s) so marked must not be
connected to a circuit point at which the voltage with respect to earth ground
exceeds 600V.
This symbol adjacent to one or more terminals identifies them as being associated
with ranges that may, in normal use, be subjected to particularly hazardous
voltages. For maximum safety, the meter and its test leads should not be handled
when these terminals are energized.
SAFETY INSTRUCTIONS
This meter has been designed for safe use, but must be operated with caution. The rules listed
below must be carefully followed for safe operation.
1. NEVER apply voltage or current to the meter that exceeds the specified maximum:
Input Protection Limits
Function Maximum Input
V DC or V AC 600V AC and DC
mA AC/DC 400mA DC/AC
A AC/DC 10A DC/AC (for 30 seconds max. every 15 minutes
Frequency, Resistance, Capacitance,
Duty Cycle, Diode, Continuity,
Temperature
250V DC/AC
2. USE EXTREME CAUTION when working with high voltages.
3. DO NOT measure voltage if the voltage on the "COM" input jack exceeds 600V above earth ground.
4. NEVER connect the meter leads across a voltage source while the function switch is in the current, resistance, or
diode mode. Doing so can damage the meter.
5. ALWAYS discharge filter capacitors in power supplies and disconnect the power when making resistance or diode
tests.
6. ALWAYS turn off power and disconnect test leads before opening the covers to replace the fuse or battery.
7. NEVER operate the meter unless the back cover and the battery and fuse covers are in place and fastened securely.
8. DO NOT use the meter if the meter or test leads look damaged, or if you suspect the meter is not operating properly.
9. If the equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may
be impaired.
WARNING
CAUTION
MAX
600V

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Controls and Jacks
1. Non-Contact AC voltage tester
2. 4000 count LCD display
3. RANGE button
4. MODE button
5. HOLD button
6. RELATIVE button
7. Function switch
8. COM (negative) input jack
9. Positive 10A input jack
10. Positive input jack
Symbols and Annunciators
•))) Continuity
Diode test
+
Low battery
HOLD Data hold
Auto Autoranging
AC Alternating current
DC Direct current
REL Relative
µ micro (amps)
m milli (volts, amps)
k kilo (ohms)
Ω Ohms
1
2
3
4
5
6
7
8
910

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OPERATING INSTRUCTIONS
WARNING: Risk of electrocution. High-voltage circuits, both AC and DC, are very dangerous and
should be measured with great care.
1. ALWAYS turn the function switch to the OFF position when the meter is not in use.
2. If OL appears in the display, the value exceeds the range you have selected. Change to a
higher range.
NOTE: On some low AC and DC voltage ranges, with the test leads not connected to a device, the
display may show a random, changing reading. This is normal and is caused by the high-input
sensitivity. The reading will stabilize and give a proper measurement when connected to a circuit.
RANGE BUTTON
When the meter is first turned on, it automatically goes into autoranging mode. To manually select
the range to be tested perform the following.
1. Press RANGE button. The AUTO display will turn off.
2. Press RANGE button to step through the available ranges.
3. Press and hold the RANGE button for 2 seconds to exit the manual ranging mode and return to
autoranging.
NOTE: Manual ranging does not apply for Capacitance, Frequency, Diode, Continuity and Duty
Cycle.
DATA HOLD BUTTON
Data hold allows the meter to “freeze” a measurement in the display.
1. Press DATA HOLD button to “freeze” the reading on the LCD. The indicator “HOLD” will appear
on the display.
2. Press DATA HOLD button to return to normal operation
RELATIVE BUTTON
The relative measurement feature allows you to make measurements relative to a stored reference
value. A reference voltage, current, etc. can be stored and measurements made in comparison to that
value. The displayed value is the difference between the reference value and the measured value.
1. Perform any measurement as described in operating instructions.
2. Press the RELATIVE button to store the reading in the display and the REL indicator will
appear on the display.
3. The display will now indicate the difference between the stored value and measured value.
4. Press the RELATIVE button to return to normal operation.

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NON-CONTACT AC VOLTAGE DETECTOR
WARNING: Always test the NCV function on a know live circuit before use
1. Turn the rotary switch to any measurement position
2. Hold the top of the meter very close to the voltage source as shown.
3. If voltage is present, the LED above the display will glowNOTE: The detector
is designed with high sensitivity. Static electricity or other sources of energy
may randomly trip the sensor. This is normal operation.
AC VOLTAGE MEASUREMENTS
WARNING: Risk of Electrocution. The probe tips may not be long enough to contact the live parts
inside some 240V outlets for appliances because the contacts are recessed deep in the outlets. As
a result, the reading may show 0 volts when the outlet actually has voltage on it. Make sure the
probe tips are touching the metal contacts inside the outlet before assuming that no voltage is
present.
CAUTION: Do not measure AC voltages if a motor on the circuit is being switched ON or OFF.
Large voltage surges may occur that can damage the meter.
1. Set the function switch to the VAC position.
2. Insert the black test lead banana plug into the negative COM jack. Insert the
red test lead banana plug into the positive Vjack.
3. Touch the black test probe tip to the neutral side of the circuit.
4. Touch the red test probe tip to the “hot” side of circuit.
5. Read the voltage in the display.

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DC VOLTAGE MEASUREMENTS
CAUTION: Do not measure DC voltages if a motor on the circuit is being switched ON or OFF.
Large voltage surges may occur that can damage the meter.
1. Set the function switch to the VDC position.
2. Insert the black test lead banana plug into the negative COM jack. Insert the
red test lead banana plug into the positive Vjack.
3. Touch the black test probe tip to the negative side of the circuit. Touch the
red test probe tip to the positive side of the circuit.
4. Read the voltage in the display.
RESISTANCE MEASUREMENTS
WARNING: To avoid electric shock, disconnect power to the unit under test and discharge all
capacitors before taking any resistance measurements. Remove the batteries and unplug the line
cords.
1. Set the function switch to the Ω position.
2. Insert the black test lead banana plug into the negative COM jack. Insert the
red test lead banana plug into the positive Ωjack.
3. Touch the test probe tips across the circuit or component under test. It is
best to disconnect one side of the circuit under test so the rest of the circuit
will not interfere with the resistance reading.
4. Read the resistance in the display.
+
-

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AC / DC CURRENT MEASUREMENTS
CAUTION: Do not make current measurements at 10 Amps for longer than 30 seconds.
Exceeding 30 seconds may cause damage to the meter and/or the test leads.
WARNING: To avoid electric shock, do not measure AC current on any circuit whose voltage
exceeds 250VAC.
1. Insert the black test lead banana plug into the negative COM jack.
2. For current measurements up to 4000µA, set the function switch to the µA position and insert
the red test lead banana plug into the mA/µA jack
3. For current measurements up to 400mA, set the function switch to the mA position and insert
the red test lead banana plug into the mA/µA jack.
4. For current measurements up to 10A, set the function switch to the 10A range and insert the
red test lead banana plug into the 10A jack.
5. Use the MODE button to select AC or DC current.
6. Remove power from the circuit under test, then open up the circuit at the point where you wish
to measure current.
7. Touch the black test probe tip to the negative side of the circuit. Touch the red test probe tip to
the positive side of the circuit.
8. Apply power to the circuit.
9. Read the current in the display.
+
-+-

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CONTINUITY CHECK
WARNING: To avoid electric shock, never measure continuity on circuits or wires that have
voltage on them.
1. Set the function switch to the position.
2. Press the MODE button to select continuity •))).
3. Insert the black lead banana plug into the negative COM jack.
4. Insert the red test lead banana plug into the positive jack.
5. Touch the test probe tips to the circuit or wire under test.
6. If the resistance is < 30, a tone will sound.
DIODE TEST
1. Set the function switch to the position.
2. Insert the black test lead banana plug into the negative COM jack and the red
test lead banana plug into the positive jack.
3. Use the MODE button to view the icon on the display.
4. Touch the test probes to the diode under test. If one reading shows a value
and the other reading shows “OL” the diode is good. Reverse voltage will
indicate “OL”. Shorted devices will indicate near 0V and an open device will
indicate “OL” in both polarities.
5. The value indicated in the display is the forward voltage.
►

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CAPACITANCE MEASUREMENTS
WARNING: To avoid electric shock, discharge the capacitor before measuring.
1. Rotate the function switch to the CAP position.
2. Press the MODE button to select capacitance (nF and a small value will
appear in the display).
3. Insert the black test lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive CAP jack.
4. Touch the black test probe tip to one side of the device.
Touch the red test probe tip to the other side of the device.
5. Read the capacitance value in the display.
Note: For very large values of capacitance measurement time can be several
seconds before the final reading stabilizes.
FREQUENCY MEASUREMENTS
1. Rotate the function switch to the Hz% position.
2. Insert the black test lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive HZ jack.
3. Touch the black test probe tip to one side of the device.
Touch the red test probe tip to the other side of the device.
4. Read the Frequency value display.

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TYPE K TEMPERATURE MEASUREMENT
1. Rotate the function switch to the °F or °C temperature
position.
2. Insert the Temperature Probe into the negative COM jack
and the TEMP jack.
3. Place the temperature probe tip where needed.
4. Read the temperature on the display.
MAINTENANCE
WARNING: To avoid electric shock, disconnect the test leads from any source of voltage before
removing the back cover or the battery or fuse covers.
WARNING: To avoid electric shock, do not operate your meter until the battery and fuse covers are
in place and fastened securely.
This MultiMeter is designed to provide years of dependable service, if the following care instructions
are performed:
1. KEEP THE METER DRY. If it gets wet, dry it immediately.
2. USE AND STORE THE METER IN NORMAL TEMPERATURES. Temperature extremes can
shorten the life of the electronic parts and distort or melt plastic parts.
3. HANDLE THE METER GENTLY AND CAREFULLY. Dropping it can damage the electronic
parts or the case.
4. KEEP THE METER CLEAN. Wipe the case occasionally with a damp cloth. DO NOT use
chemicals, cleaning solvents, or detergents.
5. USE ONLY FRESH BATTERIES OF THE RECOMMENDED SIZE AND TYPE. Remove old or
weak batteries so they do not leak and damage the unit.
6. IF THE METER IS TO BE STORED FOR A LONG PERIOD OF TIME, the battery should be
removed to prevent damage to the unit.