Major tech MT874 User manual

Operating Instruction for
True RMS Digital Multimeter
Please read this manual before switching the unit on.
Important safety information inside.
MT874
600V AC/DC TRMS
MULTIMETER
INSTRUCTION MANUAL

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1. Safety............................................................................................ 4
1.1. Safety Instructions.................................................................. 4
1.2. Safety Symbols....................................................................... 4
1.3. Input Limits............................................................................. 5
1.4. Safety Category Ratings.......................................................... 5
1.5. Test Leads............................................................................... 5
2. Description.................................................................................... 6
2.1. Meter Description.................................................................... 6
2.2. Symbols Used on LCD Display................................................ 7
3. Specifications................................................................................ 8
3.1. Specifications......................................................................... 8
3.2. General Specifications............................................................ 9
4. Battery Installation......................................................................... 10
5. Button Function............................................................................. 10
5.1. Data Hold Button..................................................................... 10
5.2. Mode/Rel Button..................................................................... 10
5.3. Auto Power Off....................................................................... 10
6. Operating Instructions................................................................... 11
6.1. DC Voltage Measurement....................................................... 11
6.2. AC Voltage Measurement....................................................... 12
6.3. DC Current Measurement....................................................... 13
6.4. AC Current Measurement....................................................... 14
6.5. Resistance Measurement....................................................... 15
6.6. Continuity Check..................................................................... 16
6.7. Diode Test............................................................................... 17
6.8. Battery Test............................................................................. 18
7. Replacing The Battery................................................................... 19
8. Replacing The Fuses.................................................................... 19
Contents Page no

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1. Safety
1.1. Safety Instructions
• This meter has been designed for safe use, but must be operated with
caution.
• The instructions listed below must be carefully followed for safe operation.
1. Never apply voltage or current to the meter that exceeds the specified
maximum:
2. Use extreme caution when working with high voltages.
3. Do not measure voltage if the voltage on the “com” input jack exceeds
600V.
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 the power and disconnect the test leads before opening
the cover to replace the fuse or batteries.
7. Never operate the meter unless the back cover, 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.
1.2. Safety Symbols
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 in 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 exceeds
600 VAC or VDC.
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. This symbol indicates
that a device is protected throughout by double insulation or
reinforced insulation.
MAX

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1.3. Input Limits
Voltage AC or DC 600 V AC/DC, 200Vrms on 200mV range
Resistance, Continuity 250 Vrms for 15 sec max
mA DC or mA AC 200mA 600V fast acting fuse
A DC or A AC 10A 600V fast acting fuse (30 seconds max
every 15 minutes)
• When the measured voltage or current exceeds the range, the buzzer will
continue to sound as a warning of exceeding the range.
1.4. Safety Category Ratings
Category Rating Brief Description Typical Applications
Single phase
receptacles and
connected loads
Three phase circuits
and single phase
lighting circuits in
commercial buildings
CAT II
CAT III
• Household appliances, power
tools
• Outlets more than 30ft (10m)
from a Cat III source
• Outlets more than 60ft (20m)
from a Cat IV source
• Equipment in fixed installations
such as 3- phase motors, switch
gear and distribution panels
• Lighting circuits in commercial
buildings
• Feeder lines in industrial plants
• Any device or branch circuit that
is close to a Cat III source
• The measurement category (CAT) rating and voltage rating is determined by a
combination of the meter, test probes and any accessories connected to the
meter and test probes.
• The combination rating is the LOWEST of any individual component.
1.5. Test Leads
CAT IV 600V
CAT III 1000V
Insulated Tip On
Insulated Tip Removed
WARNING: Operation is limited to CAT II applications when the insulated tips
are removed from one or both test probes. Refer to Input Limits section in this
manual for maximum voltage ratings.

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2.1. Meter Description
1 - LCD Display
2 - MODE/RELATIVE Button
3 - HOLD Button
4 - Function Switch
5 - 10A Input Jack
6 - Positive Input Jack
7 - COM Input Jack
8 - Lanyard Hole
9 - Test Lead Holders
10 - Battery Cover Lock
11 - Tilt Stand
12 - Battery Cover
2. Description

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1 - Auto Power Off
2 - Display Hold
3 - Relative
4 - Diode Test
5 - Continuity
6 - Units of Measure List
7 - Alternating Current
8 - Direct Current
9 - Minus Sign
10 - Battery Status
11 - Measurement Reading
2.2. Symbols Used on LCD Display

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3. Specifications
3.1.Specifications
20V 0.01V
200V ±(0.8% + 5 digits)
0.1V
Range
200mV
2V
Accuracy
±(0.5% + 5 digits)
Function
DC Voltage
Resolution
0.1mV
0.001V
600V 1V
All AC voltage ranges are specified from 5% of range to 100% of range;
AC voltage bandwidth: 50Hz to 1kHz (Sine), 50Hz to 60Hz (All wave).
200V
600V
±(1.2% + 10 digits)
AC Voltage 0.1V
1V
200mA
10A
±(1.2% + 5 digits)
DC Current 0.1mA
0.01A ±(2.0% + 5 digits)
200mA
10A
±(1.2% + 5 digits)
AC Current 0.1mA
0.01A ±(2.0% + 5 digits)
All AC Current ranges are specified from 5% of range to 100% of range;
AC Current bandwidth: 50Hz to 1kHz (Sine), 50Hz to 60Hz (All wave).
20kΩ0.01kΩ
200kΩ
±(1.0% + 5 digits)
0.1kΩ
200Ω
2kΩ±(0.8% + 5 digits)
Resistance 0.1Ω
0.001kΩ
2MΩ0.001MΩ
9V
1.5V
±(1.0% + 5 digits)
Battery Test 0.01V
0.001V
NOTE: 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.
NOTE: Accuracy is stated at 18 to 28°C (65 to 83°F) and less than 75% RH.

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3.2. General Specifications
Insulation Class 2, Double insulation.
Diode Test Test current of 1mA maximum, open circuit voltage 2V
DC typical
Continuity Check Audible signal will sound if the resistance is less than
approximately 50Ω
Battery Test current 9V (6mA); 1.5V (100mA)
Input Impedance Approximately 10MΩ (VDC and VAC)
AC Response True RMS
ACA Bandwidth 50Hz to 1kHz
ACV Bandwidth 50Hz to 1kHz
Display 3 ½ digit, 2000 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
Low Battery Indication “ ” is displayed if battery voltage drops below
operating voltage
Battery Two 1.5V “AAA” batteries
Auto Power Off Approximately 15 minutes
Fuses mA, μA ranges: 200mA/600V fast blow; A range:
10A/600V fast blow
Operating Temperature 0 to 50°C (32 to 122°F)
Storage Temperature -10 to 60°C (14 to 140°F)
Relative Humidity <70% operating, <80% storage
Operating Altitude 7000ft. (2000) meters maximum.
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. Probe assemblies to be used for mains
measurements shall be rated as
appropriate for measurement Category III according
to IEC 61010-31 and shall have a voltage rating of at
least the voltage of the circuit to be measured.
Measurement category III (CAT III) is applicable to
test and measuring circuits connected to the
distribution part of the building’s low-voltage mains
installation.

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4. Battery Installation
WARNING: To avoid electric shock, disconnect the test leads from any source
of voltage before removing the battery cover.
1. Disconnect the test leads from the meter.
2. Open the battery cover by loosening the screw using a Flat head
screwdriver.
3. Insert the battery into battery holder, observing the correct polarity.
4. Put the battery cover back in place, secure with the screw.
WARNING: To avoid electric shock, do not operate the meter until the battery
cover is in place and fastened securely.
NOTE: If your meter does not work properly, check the fuses and batteries to
make sure that they are still good and that they are properly inserted.
5. Button Function
5-1. Data Hold Button
The Data Hold function allows the meter to “freeze” a measurement for later
reference.
1. Press the Data Hold Button to “freeze” the reading on the indicator, the
indicator “H” will be appear in the display.
2. Press the Data Hold Button to return to normal operation.
5-2. Mode/Rel Button
1. Under the Diode Test/Continuity Check, press Mode/Rel Button for select
function.
2. Under Voltage/Current/Resistance measurements, pressing Mode/Rel
Button is REL function.
5-3. Auto Power Off
• The auto off feature will turn the meter off after 15 minutes.
• To disable the auto power off feature, hold down the Mode/Rel Button and
turn the meter on.
Note: The above data only for reference.