Extech Instruments MN26-NIST User manual

User’s Manual
MiniTecTM Series
Model MN26
Mini Autoranging
MultiMeter

2
Introduction
Congratulations on your purchase of Extech’s MN26 Autoranging
Multimeter. This meter measures AC/DC Voltage, AC/DC Current,
Resistance, Capacitance, Frequency, Duty Cycle, Temperature, Diode
Test and Continuity. Proper use and care of this meter will provide many
years of reliable service.
Safety
International Safety Symbols
This symbol, adjacent to another symbol or terminal,
indicates the user must refer to the manual for further
information.
This symbol, adjacent to a terminal, indicates that, under
normal use, hazardous voltages may be present
Double insulation
Safety Precautions
1. Improper use of this meter can cause damage, shock, injury or
death. Read and understand this user manual before operating the
meter.
2. Make sure any covers or battery doors are properly closed and
secured.
3. Always remove the test leads before replacing the battery or fuses.
4. Inspect the condition of the test leads and the meter itself for any
damage before operating the meter. Repair any damage before
use.
5. Do not exceed the maximum rated input limits.
6. Use great care when making measurements if the voltages are
greater than 25VAC rms or 35VDC. These voltages are considered
a shock hazard.

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7. Always discharge capacitors and remove power from the device
under test before performing Capacitance, Diode, Resistance or
Continuity tests.
8. Remove the battery from the meter if the meter is to be stored for
long periods.
9. To avoid electric shock, do not measure AC current on any circuit
whose voltage exceeds 250V AC.
10. Voltage checks on electrical outlets can be difficult and misleading
because of the uncertainty of connection to the electrical contacts.
Other means should be used to ensure that the terminals are not
"live".
Specifications
Function Range Resolution Accuracy
400mV 0.1mV ±(0.5% reading + 2 digits)
4V 0.001V
40V 0.01V
400V 0.1V
±(1.0% reading + 2 digits)
DC Voltage
(V DC)
600V 1V ±(1.5% reading + 2 digits)
400mV 0.1mV ±(2.0% reading + 30 digits)
4V 0.001V
40V 0.01V
400V 0.1V
±(1.5% reading + 3 digits)
AC Voltage
(V AC)
(40 - 400Hz)
(40 - 200Hz for
400mV, 4V
ranges) 600V 1V ±(2.0% reading + 4 digits)
400µA 0.1µA
4000µA 1µA
40mA 0.01mA
400mA 0.1mA
±(1.5% reading + 3 digits)
DC Current
(A DC)
10A 0.01A
±(2.5% reading + 5 digits)

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Function Range Resolution Accuracy
400µA 0.1µA
4000µA 1µA
40mA 0.01mA
400mA 0.1mA
±(1.8% reading + 5 digits)
AC Current
(A AC)
(40 - 400Hz)
(40 - 200Hz for
400µA, 4mA
ranges) 10A 0.01A
±(3.0% reading + 7 digits)
400Ω0.1Ω±(1.2% reading + 4 digits)
4kΩ0.001kΩ
40kΩ0.01kΩ
400kΩ0.1kΩ
4MΩ0.001MΩ
±(1.2% reading + 2 digits)
Resistance
40MΩ0.01MΩ±(2.0% reading + 3 digits)
4nF 0.001nF
±(5.0% reading + 10digits)
40nF 0.01nF
±(5.0% reading + 7 digits)
400nF 0.1nF
4µF 0.001µF
40µF 0.01µF
±(3.5% reading + 5 digits)
Capacitance
200µF 0.1µF ±(5.0% reading + 5 digits)
9.999Hz 0.001Hz
99.99Hz 0.01Hz
±(1.5% reading + 5 digits)
999.9Hz 0.1Hz
9.999kHz 0.001kHz
99.99kHz 0.01kHz
999.9kHz 0.1kHz
±(1.2% reading + 2 digits)
9.999MHz 0.001MHz ±(1.5% reading + 4 digits)
Frequency
Sensitivity: 0.8V rms min. @ 20% to 80% duty cycle and
<100kHz; 5Vrms min @ 20% to 80% duty cycle and >
100kHz.

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Function Range Resolution Accuracy
Duty Cycle 0.1 to 99.9% 0.1% ±(1.2% reading + 2 digits)
Pulse width: 100µs - 100ms
Temp °F -4 to 1400°F 1°F
Temp °C -20 to 760°C 1°C
±(3.0% reading + 3 digits)
(probe % not included)
Input Limits
Function Maximum Input
V DC, VAC 600V DC/AC
Ohms, Capacitance, Diode,
Frequency, Continuity
250V DC/AC
mA DC/AC 400mA DC/AC
10A DC/AC 10A DC/AC (30sec. max)
NOTE: Accuracy is stated at 65oF to 83oF (18oC to 28oC) and less than
70% RH.
Diode Test Test current of 0.3mA maximum, open
circuit voltage 1.5V DC typical
Continuity Check Audible signal will sound if the resistance is
less than approximately 30Ω, test current
<0.7mA
Temperature sensor Requires type K thermocouple
Input Impedance 7.5MΩ(VDC and VAC)
Display 4000 count LCD
Overrange indication “OL” is displayed
Polarity Automatic (no indication for positive
polarity); Minus (-) sign for negative polarity.
Measurement Rate 2 times per second, nominal
Auto Power Off Meter automatically shuts down after 15
minutes of inactivity
Low Battery Indication “BAT” is displayed if battery voltage drops
below operating voltage
Batteries Requires two AAA batteries

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1
2
5
6
3
4
7
10
9
8
Fuses mA, µA ranges, 0.5A/250V fast blow
10A range, 10A/250V fast blow
Operating Temperature 32oF to 122oF (0oC to 50oC)
Storage Temperature -4oF to 140oF (-20oC to 60oC)
Relative Humidity <70% operating, <80% storage
Operating Altitude 7000ft (2000 meters) maximum.
Weight 9.17 oz. (260g).
Size 4.78” x 2.38” x 1.57” (121.5mm x 60.6mm x
40mm)
Safety For indoor use and in accordance with
Overvoltage Category II, Pollution Degree 2.
Category II includes local level, appliance,
portable equipment, etc., with transient
overvoltages less than Overvoltage
Category III.
Meter Description
1. LCD Display
2. Function switch
3. Function key
4. Range key
5. Temperature jack
6. COM jack
7. 10A jack
8. Positive jack
9. Relative key
10. Data Hold key
Note: Tilt stand, fuse and battery compartment are on rear of unit.

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Symbols
AC (alternating current or voltage)
DC (direct current or voltage)
•))) Continuity
Diode test
mV, V millivolt, volt (voltage)
Ω, kΩ, MΩ ohm, kilohm, megohm (resistance)
uA, mA, A microamp, milliamp, Amp (current)
pF, nF, uF picofarad, nanofarad, microfarad (capacitance)
Hz kHz hertz, kilohertz (frequency)
% % duty cycle
OF, OC Degrees fahrenheit, centigrade (temperature)
AUTO Autorange
BAT Low battery
HOLD Display hold
REL Relative
Operating Instructions
AC or DC Voltage Measurements
1. Insert the black test lead banana plug into the negative COM jack
and the red test lead banana plug into the positive Vjack.
2. Turn the rotary switch to the VAC or VDC position.
3. Touch the test probes to the circuit under test and read the voltage
on the display.

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AC or DC Current Measurements
CAUTION: Do not make current measurements on the 10A scale for
longer than 30 seconds followed by a 15 minute cool down period.
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
and the red test lead banana plug into the;
a. Positive uA/mA jack for currents to 400mA
b. Positive 10A jack for currents to 10A
2. Turn the rotary switch to the uA, mA or Aposition.
3. Touch the test probes in series with the circuit under test and read
the current on the display.
Resistance Measurements
1. Insert the black test lead banana plug into the negative COM jack
and the red test lead banana plug into the positive Ωjack.
2. Turn the rotary switch to the Ωposition.
3. Touch the test probes to the circuit or device under test and read
the resistance on the display.
Capacitance Measurements
1. Insert the black test lead banana plug into the negative COM jack
and the red test lead banana plug into the positive CAP jack.
2. Turn the rotary switch to the CAP position.
3. Touch the test probes to the circuit or device under test and read
the capacitance on the display.
Frequency or Duty Cycle Measurements
1. Insert the black test lead banana plug into the negative COM jack
and the red test lead banana plug into the positive HZ jack.
2. Turn the rotary switch to the Hz/% position.
3. Press the Hz/% key to select “Hz” or “%”.
4. Touch the test probes to the circuit or under test and read the
frequency or duty cycle on the display.

9
Temperature Measurements
WARNING: To avoid electric shock, disconnect test leads from any
source of voltage before making a temperature measurement. Be sure
that the thermocouple has been removed before changing to any other
measurement function.
1. Insert the type K thermocouple probe into the sub-miniature
temperature socket.
2. Turn the rotary switch to the oCor oFposition.
3. Read the temperature on the display.
Continuity Measurements
1. Insert the black test lead banana plug into the negative COM jack
and the red test lead banana plug into the positive Ωjack. Observe
polarity.
2. Turn the rotary switch to the •))) position.
3. Press the •))) key to select continuity.
4. Touch the test probes to the circuit or device under test. If the
resistance is less than approximately 30Ωthe buzzer will sound
and the resistance appears on the display.
Diode Measurements
1. Insert the black test lead banana plug into the negative COM jack
and the red test lead banana plug into the positive diode jack.
2. Turn the rotary switch to the •))) position.
3. Press the •))) key to select diode.
4. Touch the test probes to the diode under test. Forward voltage will
indicate 0.4V to 0.7V. Reverse voltage will indicate “OL”. Shorted
devices will indicate near 0mV and an open device will indicate
“OL” in both polarities.

10
Manual Ranging
The meter powers on in the autoranging mode. Press the Range key to
go to manual ranging. Each press of the range key will step to the next
range as indicated by the units and decimal point location. Press and
hold the Range key for one second to return to autoranging.
Data Hold
Press the Data Hold key to freeze the reading in the display. “HOLD”
will appear in the LCD. Press the key again to release the display.
Relative Measurements
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 the 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 the measured value.
4. Press the Relative button to return to normal operation.
Auto Off
The auto off feature will turn the meter off after 15 minutes of inactivity
(Range switch or a key has not been turned or pressed). A beep will
warn the user shortly before the auto off feature activates.

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Maintenance
WARNING: To avoid electric shock, disconnect the test leads from
any source of voltage before removing the battery/fuse cover.
WARNING: To avoid electric shock, do not operate your meter until
the battery/fuse cover is 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.
2. Use and store the meter in mild ambient conditions. Temperature
extremes can shorten the life of the electronic parts and distort or
melt plastic parts.
3. Handle the meter gently. 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 batteries
should be removed to prevent damage to the unit.

12
Battery Replacement
WARNING: To avoid electric shock, disconnect the test leads from
any source of voltage before removing the battery/fuse cover.
1. Disconnect the test leads from the meter.
2. Remove the rubber holster (if in place).
3. Open the battery door by removing the screw
using a Phillips head screwdriver.
4. Insert the new batteries into the battery holder,
observing the correct polarity.
5. Replace the battery door and secure with the
screw.
Fuse Replacement
WARNING: To avoid electric shock, disconnect the test leads from
any source of voltage before removing battery/fuse cover.
1. Disconnect the test leads from any circuit being measured.
2. Remove the rubber holster (if in place).
3. Open the fuse cover by removing the screw on the rear cover using
a Phillips screwdriver.
4. Remove the rear cover.
5. Remove the old fuse by gently pulling up on it.
6. Install the new fuse by gently pushing it into the holder.
7. Always use a fuse of the proper size and value (0.5A/250V fast
blow, or 10A/250V fast blow).
8. Replace the fuse door and secure with the screw.
A UL mark does not indicate that this product has been evaluated for the
accuracy of its readings.

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Warranty
EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects
in parts and workmanship for one year from date of shipment (a six month limited
warranty applies on sensors and cables). If it should become necessary to return the
instrument for service during or beyond the warranty period, contact the Customer
Service Department at [phone] ext. 210 for authorization or visit our website at
www.extech.com (click on ‘Contact Extech’ and go to ‘Service Department’ to request an
RA number). A Return Authorization (RA) number must be issued before any product is
returned to Extech. The sender is responsible for shipping charges, freight, insurance
and proper packaging to prevent damage in transit. This warranty does not apply to
defects resulting from action of the user such as misuse, improper wiring, operation
outside of specification, improper maintenance or repair, or unauthorized modification.
Extech specifically disclaims any implied warranties or merchantability or fitness for a
specific purpose and will not be liable for any direct, indirect, incidental or consequential
damages. Extech's total liability is limited to repair or replacement of the product. The
warranty set forth above is inclusive and no other warranty, whether written or oral, is
expressed or implied.
Calibration and Repair Services
Extech offers complete repair and calibration services for all of the
products we sell. For periodic calibration, NIST certification or repair of any
Extech product, call customer service for details on services available.
Extech recommends that calibration be performed on an annual basis to
insure calibration integrity.
Copyright ©2002 Extech Instruments Corporation.
All rights reserved including the right of reproduction
in whole or in part in any form.
MN26 V1.3 6/02

Tech Support Hotlines
781-890-7440 ext. 200 [email protected] www.extech.com