OPERATING INSTRUCTIONS
MODEL 2708B
DIGITAL MULTIMETER
A mA
COM V
10A
2708B
SAFETY INFORMATION
The following safety information must be observed to ensure maximum personal
safety during the operation at this meter:
Use the meter only as specified in this manual or the protection provided by the
meter might be impaired.
Test the meter on a known voltage before using it to determine if hazardous
voltage is present.
Do not use the meter if themeter or test leads look damaged, or if you suspect
that the meter is not operating properly.
Never ground yourself when taking electrical measurements. Do not touch
exposed metal pipes, outlets, fixtures, etc., which might be at ground potential.
Keep your body isolated from ground by using dry clothing, rubber shoes, rubber
mats, or any approved insulating material.
Turn off power to the circuit under test before cutting, unsoldering, or breaking
the circuit. Small amounts of current can be dangerous.
Use caution when working above 60V dc or 30V ac rms. Such voltages pose a
shock hazard.
When using the probes, keep your fingers behind the finger guards on the
probes.
Measuring voltage which exceeds the limits of the multimeter may damage the
meter and expose the operator to a shock hazard.Always recognize the meter
voltage limits as stated on the front of the meter.
SPECIFICATIONS
Display: 3¾ digit liquid crystal display (LCD) with a maximum reading of
Analog bar graph: 34 segments with measurements 12 times per second.
Polarity:Automatic, positive implied, negative polarity indication.
Overrange: (OL) or (-OL) is displayed.
Zero:Automatic.
Low battery indication: The " " is displayed when the battery voltage
belowthe operating level.
Measurement rate: 2 times per second, nominal.
Auto power off:Approx. 10 minutes.
Operating environment: 0℃to 50℃at < 70% relative humidity.
Storage temperature: -20℃to 60℃, 0 to 80% relative humidity.
Accuracy: Stated accuracy at 23℃±5℃, < 75% relative humidity.
Temperature Coefficient: 0.1 x(specified accuracy) per ℃. (℃to 18℃,
50℃).
Altitude: 6561.5 feet (2000m).
Power: Single standard 9-volt battery, NEDA1604, JIS 006P, IEC 6F22.
Battery life: 150 hours typical with carbon-zinc.
Dimensions: 165mm (H) x78mm (W)x42.5mm (D).
Weight:Approx. 10.0oz.(285g) including holster.
Accessories: One set test leads, one spare fuse, 9V battery (installed), and
Operating Instructions.
DC VOLTS
Ranges: 340mV, 3.4V, 34V, 340V, 1000V
Resolution: 0.1mV
Accuracy: ±(1.0% rdg+2dgts )
Input impedance: 340mV: >100MΩ; 3.4V:10MΩ; 34V ~1000V:9.1MΩ
Overload protection: 1000VDC or750VAC rms
AC VOLTS (TRUE RMS) (50Hz – 1kHz)
Ranges: 3. 4V, 34V, 340V, 750V
Resolution: 1mV
Accuracy: ±(2.0% rdg + 8dgts)50 ~ 1kHz on 3.4V, 34V ranges
±( 2.0% rdg + 8dgts)50 ~ 500Hz on 340V, 600V ranges
Input impedance: 3.4V: >10MΩ; 34V ~ 750V:9.1MΩ
Overload protection: 1000VDC or750VAC rms
CURRENT
Ranges: 340uA, 3400uA, 34mA, 340mA, 10A
Resolution: 0.1uA
DC accuracy:
±( 2.0% rdg + 2 dgts) on 340uAto 340mAranges
±( 3.0% rdg + 3 dgts) on 10Arange
AC accuracy: (TRUE RMS) (50Hz ~ 500Hz)
±( 2.5% rdg + 10dgts) on 340uAto 340mAranges
±( 3.5% rdg + 10dgts) on 10Arange
Voltage burden: 0.2V on 340uA, 34mA, 10Aranges
2V on 3400uA, 340mAranges
Input protection: 0.5A/500V fast blowceramic fuse
10A/600V fast blow ceramic fuse
10A Input: 10Afor 60 seconds maximum followed
by a 10 minute cooling period
RESISTANCE
Ranges: 340Ω, 3.4kΩ, 34kΩ, 340kΩ, 3.4MΩ, 34MΩ
Resolution: 0.1Ω
Accuracy:
±(1.5% rdg + 4 dgts) on 340Ωto 340kΩranges
±(2.5% rdg +4 dgts) on 3.4MΩrange
±(5.0% rdg + 5 dgts) on 34MΩrange
Open circuit volts typical: -0.45Vdc (-1.2Vdc on 340Ωrange)
Overload protection: 500VDC orAC rms
DIODE TEST
Test current: 1.0mA(approximate)
Accuracy: ±(3.0% rdg + 3 dgts)
Resolution: 10mV
Audible indication: <0.25V
Open circuit volts: 3.0Vdc typical
Overload protection: 500VDC orAC rms
CONTINUITY
Audible indication: Less than 35Ω
Response time: 500ms
Overload protection: 500VDC orAC rms
OPERATION
Before taking any measurements, read the Safety Information Section.
examine the instrument for damage, contamination (excessive dirt, grease,
and defects. Examine the test leads for cracked or frayed insulation. If any
abnormal conditions exist do not attempt to make anymeasurements.
Input Warning Beeper
The meter has a beeper that warns the user when the test lead is in the current
jack while the meter is switched tomake a voltage measurement.Another safety
feature to protect the meter and you.
Data Hold
Press [HOLD] button to lock the reading on display, and release it by pressing
the button again.
Manually Selecting Range
The meter also has amanual range mode. In manual range, you select and lock
the meter in a range. To manually select a range:
Press [RANGE] button to hold the selected range. Subsequently pressing the
[RANGE] button will select each range in sequence from the lowest to highest
range. Hold the button for 2 seconds to return to theAutorange Mode.
Voltage Measurements
1.Connect the red test lead to ”VΩ”jack and the black test lead to the ”COM”
jack.
2.Set the Function/Range switch to the desired voltage type (AC or DC) and
range. If magnitude of voltage is not known, set switch to the highest range
and reduce until a satisfactory reading is obtained.
3.Connect the test leads to the device or circuit being measured.
4. For dc, a (-) sign is displayed for negative polarity; positive polarity is implied.
Current Measurements
1.Connect the red test lead to the (uA, mAor 10A) jack and the black test lead to
the "COM" jack.
2.Set the Function/Range switch to the DC orAC ranges.
3.Remove power from the circuit under test and open the normal circuit path
where the measurement is to be taken. Connect the meter in series with the
circuit.
4.Apply power and read the value from the display.
Resistance Measurements
1.Set the Function/Range switch to the desired resistance range.
2.Remove power from the equipment under test.
3.Connect the red test lead to the " VΩ" jack and the black test lead to the
"COM" jack.
4.Connect the test leads to the points of measurements and read the value from
the display.
Diode Tests
1.Connect the red test lead to the “VΩ” jack and the black test lead to
the ”COM” jack.
2.Set the Function/Range switch to the “ “ position.
3.Turn off power to the circuit under test. External voltage across the
components causes invalid readings.
4.Touch probes to the diode.A forward-voltage drop is about 0.6V (typical for a
silicon diode).
5.Reverse probes. If the diode is good, “OL”is displayed. If the diode is shorted,
“000” or another number is displayed.
6. If the diode is open,“OL” is displayed in both directions.
7.Audible Indication: Less than 0.25V.
Continuity Measurements
1.Set the Function switch to the position.
2.Turn off power to the circuit under test. External Voltage across the
components causes invalid reading.
3.Connect the test leads to the two points at which continuity is to be tested. The
buzzer will sound if the resistance is less than approximately35Ω.
Auto Power Off
1.Auto power off: approx. 10 minutes.
2.After auto power off, press any button to restart the meter, and the reading of
measurement will be maintained in the display.
Cancellation of Auto Power Off Feature:
Press and hold the (RANGE) button while rotating function switch from off to
any position to turn the meter on. The auto power off feature is disabled.
Note“APO”annunciator is missing from the LCD.
MAINTENANCE
WARNING
Remove test leads before changing battery or fuse or
performing any servicing.
Battery Replacement
Power is supplied by a 9 volt battery. (NEDA1604, IEC 6F22). The " " appears
on the LCD display when replacement is needed. To replace the battery, remove
the three screws from the back of the meter and lift off the front case.Remove
the battery from case bottom.
Fuse Replacement
If no current measurements are possible. Check for a blown overload protection
fuse. For access to fuses, remove the three screws from the back of the meter
and lift off the front case. Replace F1 only with the original type 0.5A/500V, fast
acting ceramic fuse, 6.35x32mm Replace F2 only with the original type
10A/600V, fast acting ceramic fuse 6.35x25.4mm.
Cleaning
Wipe the case with a damp cloth and mild detergent. Do not use abrasives or
solvents. Dirt ormoisture in the terminals can affect readings.
Safety: Conforms to IEC61010-1 (EN61010-1),CATII 1000V, CATIII 600V, Class
II, Pollution degree 2 Indoor use.
CATII: Is for measurements performed on circuits directly connected to the
low-voltage installation.
CAT III: Is for measurements performed in the building installation.
EMC: Conforms to EN61326.
The symbols used on this instrument are:
Caution, refer to accompanying documents
Equipment protected throughout by Double insulation (Class II)
Alternating current
Direct current
Ground
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