Extech Instruments MN15A User manual

User's Guide
Mini Digital Multimeter
Model MN15A
A

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Introduction
Congratulations on your purchase of the Extech MN15A MultiMeter. The MN15A offers
AC/DC Voltage, AC/DC Current, Resistance, Diode, and Continuity testing plus Type K
thermocouple temperature measurements. 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.
This symbol indicates that a device is protected throughout by double
insulation or reinforced insulation.
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
VDC or VAC 600VAC and VDC
VDC or VAC 200mV range 200Vrms
mA AC/DC 200mA 250V fast acting fuse
A AC/DC 10A 250V fast acting fuse
(for 30 seconds max. every 15 minutes.)
Resistance, Continuity 250Vrms for 15 sec. max.
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. 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. LCD display
2. Rotary function switch
3. 10 ampere test lead jack
4. Test lead jack for voltage, milliamp,
resistance/continuity, diode and temperature functions
5. COM test lead jack
6. Battery compartment (rear)
SYMBOLS
•))) Continuity Diode
AC DC
M megga (106) (ohms) m milli (10-3) (volts, amps)
k kilo (103) (ohms) V Volts
A Amps Ω Ohms
BAT Battery test °C Degrees Celsius
°F Degrees Fahrenheit Low battery indicator

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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.
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.
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 600 VAC position.
2. Insert the black test lead banana plug into the negative COM jack.
Insert 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.
6. If the reading is less than 200V, switch to the 200V range to improve
resolution.
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 highest 600VDC 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.
5. If the reading is less than the maximum of a lower range, switch to that
range to improve resolution.

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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.
1. Insert the black test lead banana plug into the negative COM jack.
2. For current measurements up to 200mA, set the function switch to
the 200mA position and insert the red test lead banana plug into the
mA jack.
3. For current measurements up to 10A, set the function switch to the
10A position and insert the red test lead banana plug into the 10A
jack.
4. Remove power from the circuit under test, then open up the circuit at the point where
you wish to measure current.
5. 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.
6. Apply power to the circuit.
7. Read the current in the display.

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RESISTANCE MEASUREMENTS
WARNING: To avoid electric shock, disconnect power to the unit under test and discharge
all capacitors before taking any resistance measurements.
1. Set the function switch to the highest 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 part under test.
4. Read the resistance in the display. Move the function switch to
successively lower Ωranges to obtain a higher resolution reading.
CONTINUITY CHECK
WARNING: To avoid electric shock, never measure continuity on circuits that have a
voltage potential.
1. Set the function switch to the position.
2. Insert the black 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 to the circuit or wire you wish to check.
4. If the resistance is less than approximately 100Ω, the audible signal
will sound. If the circuit is open, the display will indicate “1. ”.
DIODE TEST
1. Set the function switch to the position.
2. Insert the black test lead banana plug into the negative COM jack
Insert the red test lead banana plug into the positive jack.
3. Touch the test probes to the diode under test.
4. A typical diode will indicate approximately .400 to .500 volts for the
forward test and “1. ” for the reverse test.
5. A shorted diode will indicate a low value in both the reverse and
forward test directions. An open diode will indicate “1. ” in both test
directions.

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BATTERY VOLTAGE TEST
CAUTION: Do not measure batteries while they are installed in the devices they are
powering. The batteries must be removed from installations before tests can be made.
1. Set the function switch to the 1.5V or 9V BAT switch position. Use the
1.5V position for ‘AAA’, ‘AA’, ‘C’, ‘D’, and other 1.5V batteries. Use the
9V position for square 9V transistor batteries.
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 battery.
Touch the red test probe tip to the positive side of the battery.
4. Read the voltage in the display.
TEMPERATURE MEASUREMENTS
1. Set the function switch to the °F or °C position.
2. Insert the Temperature Probe into the COM and Temp jacks, making
sure to observe the correct polarity.
3. Touch the Temperature Probe head to the part to be measured. Keep
the probe touching the part under test until the reading stabilizes.
4. Read the temperature in the display.
Note: The temperature probe is fitted with a type K mini connector.
A mini connector to banana connector adaptor is supplied for
connection to the input banana jacks.

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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, wipe it off.
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.
BATTERY/FUSE INSTALLATION and LOW BATTERY INDICATION
WARNING: To avoid electric shock, disconnect the test leads from any source of voltage
before removing the battery cover. Do not operate meter unless the battery is in place.
LOW BATTERY INDICATION
The icon will appear in the display when the battery voltage becomes low. Replace the
battery when this appears.
BATTERY REPLACEMENT
1. Disconnect the test leads from the meter.
2. Remove the 2 Phillips head screws located on the back of the instrument and remove
the battery cover.
3. Replace the 9V battery.
4. Secure the fuse/battery compartment cover.
5. Dispose of the old battery as required by local regulations.
FUSE REPLACEMENT
1. Disconnect the test leads from the meter.
2. Remove the 2 Phillips head screws located on the back of the instrument and remove
the battery cover.
3. Gently remove the fuse(s) and install the new fuse(s) into the holder(s).
4. Always use fuses of the proper size and value (200mA/660V ceramic fast blow for the
mA / µA ranges, 10A/250V ceramic fast blow for the A range).
5. Secure the fuse/battery compartment cover.
WARNING: To avoid electric shock, do not operate your meter until the fuse cover is in
place and fastened securely.

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Range Specifications
Function Range Resolution Accuracy
DC Voltage
(V DC)
200mV 0.1mV
±(0.5% reading + 2 digits)
2000mV 1mV
20V 0.01V
200V 0.1V
±(0.8% reading + 2 digits)
600V 1V
AC Voltage
(V AC)
200V 0.1V
±(1.2% reading + 10 digits
(50/60Hz)
600V 1V
DC Current
(A DC)
200mA 0.1mA
±(1.2% reading + 2 digits)
10A 10mA
±(2.0% reading + 2 digits)
Resistance
200Ω0.1Ω
±(0.8% reading + 2 digits)
2000Ω1Ω
20kΩ0.01kΩ
200kΩ0.1kΩ
20MΩ10kΩ±(1.5% reading + 2 digits)
Battery Test 9V 10mV
±(1.0% reading + 2 digits)
1.5V 1mV
Temperature -20°C to 750°C 1°C
±(3% of reading +5°C/9°F)
-4°F to 1400°F 1°F
Notes:
Accuracy specifications consist of two elements:
•(% reading) – This is the accuracy of the measurement circuit.
•(+ digits) – This is the accuracy of the analog to digital converter.
Accuracy is stated at 65oF to 83oF (18oC to 28oC) and less than 75% RH.

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General Specifications
Diode Test Bias voltage: 2.8VDC typical
Continuity Check Audible signal will sound if the resistance is less than 100Ω
Input Impedance 1MΩ(VDC & VAC)
AC Bandwidth 50 / 60Hz
Display 2000 count (0 to 1999) LCD
Overrange indication “1___” is displayed
Polarity Automatic (no indication for positive); Minus (-) sign for
negative
Measurement Rate 2 times per second, nominal
Low Battery Indication “ ” is displayed
Battery One (1) 9V battery (NEDA 1604)
Fuses mA range; 200mA/250V ceramic fast blow
A range; 10A/250V ceramic fast blow
Operating Temperature 32ºF to 122ºF (0ºC to 50ºC)
Storage Temperature -4oF to 140oF (-20oC to 60oC)
Operating Humidity Max 70% up to 87ºF (31ºC) decreasing linearly to 50% at
122ºF (50ºC)
Storage Humidity < 80% RH
Operating Altitude 7000 ft. (2000 meters) maximum.
Weight 9.17 oz (255g)
Size 5.2” x 2.6” x 1.5” (132 x 66 x 38mm)
Approvals CE, ETL
Safety This meter is intended for indoor use and protected, against
the users, by double insulation per EN61010-1 and IEC61010-
1 2nd Edition (2001) to CAT III 600V; Pollution Degree 2. The
meter also meets UL 61010-1, Second Edition (2004),
CAN/CSA C22.2 No. 61010-1, Second Edition (2004), and UL
61010B-2-031, First Edition (2003)
PER IEC1010 OVERVOLTAGE INSTALLATION CATEGORY
OVERVOLTAGE CATEGORY I
Equipment of OVERVOLTAGE CATEGORY I is equipment for connection to circuits in
which measures are taken to limit the transient overvoltages to an appropriate low level.
Note – Examples include protected electronic circuits.
OVERVOLTAGE CATEGORY II
Equipment of OVERVOLTAGE CATEGORY II is energy-consuming equipment to be
supplied from the fixed installation.
Note – Examples include household, office, and laboratory appliances.
OVERVOLTAGE CATEGORY III
Equipment of OVERVOLTAGE CATEGORY III is equipment in fixed installations.
Note – Examples include switches in the fixed installation and some equipment for
industrial use with permanent connection to the fixed installation.
OVERVOLTAGE CATEGORY IV
Equipment of OVERVOLTAGE CATEGORY IV is for use at the origin of the installation.
Note – Examples include electricity meters and primary over-current protection equipment