Tenma 72-7780 User manual

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True RMS Digital Multimeter
Model: 72-7780

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This meter is designed to meet IEC61010-1, 61010-2-032, and 61010-2-033 in
Pollution Degree 2, Measurement Category (CAT II 600V, CAT III 600V) and double
Insulation.
• Do not operate the meter or use test leads if they appear damaged, or if the meter
is not operating properly.
• There are no user-serviceable parts in this product. Refer servicing to qualied
personnel.
• Do not apply voltage between the COM and OHM terminals, while in the
resistance measuring state.
• Do not measure current with the test leads inserted into the voltage or OHM
terminals.
• To avoid electrical shock and personal injury, do not attempt to measure voltage
higher than 600V AC/DC, although the readings may be obtained.
• Do not expose the instrument to direct sunlight, extreme temperature or humidity.
• Before measuring current, check the fuses and turn the power to the circuit off
before connecting the meter to the circuit.
• Disconnect circuit power and discharge all high voltage capacitors before testing
continuity. diode, resistance, capacitance or current.
• Take caution when voltages are above 60V DC and 30V AC rms.
• Do not use the meter around explosive gas or vapour.
• When using the test leads, keep your ngers behind the nger guards.
• Remove test leads from the meter before opening the meter case or battery door.
• Never operate the meter with the cover removed or the battery door open.
• Use only the test leads supplied or the protection may be impaired.
• Probe assemblies for mains measurements shall be rated as appropriate for
measurement category III according to IEC 61010-031 and shall have a voltage
RATING of at least the voltage of the circuit to be measured.
• Replace the batteries as soon as the low battery indicator appears on the display.
• Remove dead batteries from the meter or if it is not going to be used for a long
time.
• Never mix old and new batteries together, or different types of batteries.
• Never dispose of batteries in a re, or attempt to recharge ordinary batteries.
• Before replacing the battery, turn off the meter and disconnect all the test probes.
• To prolong battery life turn off the meter after use.
SAFETY INFORMATION
Please read these instructions carefully before use and retain for future
reference.
WHAT’S INCLUDED
• Digital multimeter
• User manual
• Cat III 600V test lead
• Point type K thermocouple
• Current clamp

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SYMBOL GUIDE
AC or DC
Grounding
Double insulated
Warning
Low battery
Continuity Buzzer
Diode
Fuse
Conforms to European Union directives
FUNCTIONS
1. Casing
2. LCD Display
3. Function buttons x 4
4. Option buttons
5. Range selector
6. Test lead input terminals
1
2
3
4
5
6
4
r Mk Ω Hz nm Vµ AF
oC oF
%
DC
AC
-8 . 8 . 8 . 8
MAX-MIN Auto Range NCV A
H
Display symbol Instruction
H
Data hold prompt
-- Negative reading
AC/DC AC/DC measurement
MAX-MIN Max/Min value measurement prompt
Low voltage internal battery
Auto Range Uto range prompt

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Display symbol Instruction
Diode measurement prompt
Circuit on/off measurement prompt
rRelative measurement prompt
Ω / kΩ / MΩ Resistance units
Hz / kHz / MHz Frequency units
%Duty ratio measurement unit
mV / V Voltage units
µA/mA/A Current units
nF/µF/mF Capacitance units
oCCentigrade temperature unit
oFFahrenheit temperature unit
(EF)NCV non contact AC voltage sensing
Auto power off
Current clamp
RANGE button
• The range button selects between auto and manual range when measuring
voltage, impedance or resistance.
• Press it repeatedly to select high range or low range.
• Press and hold for more than 2 seconds and the meter will exit manual range.
MAX/MIN button
• This button is used to switch into the manual range mode when auto shutdown is
disabled. Voltage, resistance, impedance and temperature
• The maximum value is displayed initially.
• Pressing the button again displays the minimum value.
• Press and hold for more than 2 seconds and the meter will exit data recording
mode.
REL button
• Press to enter the manual range mode. The displayed value will be taken as
reference value and the difference between the reference value and the measured
value will be displayed.
• Press again to exit the measurement mode.
Hz/% button
• Press to switch between measurement of frequency, AC voltage/current modes.
Select button
• Used to select between UFC and VFC modes when measuring AC voltage.
• Press and hold for 2 seconds to switch between modes or end the selection.
HOLD button
• Lock and hold the displayed value, press again to return to normal.

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OPERATING PARAMETERS
• Operating temperature: 23°C± 5°C
• Relative Humidity: ≤75%.
• Temperature Coefcient: 0.1× (specied accuracy)/1°C
DC VOLTAGE
Range Resolution Accuracy Overload Protection
60.00mV 10µV ±(0.5%+2)
600V DC/AC
600.00mV 0.1mV
6.000V 1mV
±(0.7%+3)
60.00V 10mV
600.0V 0.1V
600V 1V
Note: The input impedance is 10MΩ.
AC VOLTAGE
Range Resolution Accuracy Overload Protection
60.00mV 10µV ±(1.0%+3)
600V DC/AC
600.0mV 0.1mV
6.000V 1mV
±(0.8%+3)60.00V 10mV
600.0V 0.1V
600V 1V ±(1.0%+3)
VFC 200.0V~600V ±(4.0%+3) 0.1/1V
Notes:
• Input Impedance: ~10MΩ
• Frequency Response: 45Hz~1KHz (VFC: 45~400Hz)
• Maximum input voltage: 600Vrms
RESISTANCE
Range Resolution Accuracy Overload Protection
600.0Ω 0.1Ω ±(1.0%+2)
600Vp
6.000kΩ 1Ω
±(0.8%+2)60.00kΩ 10Ω
600.0kΩ 100Ω
6.000MΩ 1kΩ ±(1.2%+2)
60.00MΩ 10kΩ ±(1.5%+2)

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Range Resolution Accuracy Overload Protection
1mV Displays approximate
forward voltage drop 600Vp
Range Resolution Accuracy Overload Protection
9.999nF 1pF Under REL status
±(4%+10) 600Vp
99.99nF~999.9µF 10pF~0.1µF ±(4%+5)
9.999nF~99.99mF 1µF~10µF ±10%(≤2mF)
DIODE AND CONTINUITY
Range Resolution Accuracy Overload Protection
0.1Ω When ≤10Ω, the
buzzer beeps. 600Vp
Notes:
• The open circuit voltage is about *1V.
• The buzzer may beep when the resistance of a circuit under test is <10Ω.
• The buzzer does not beep when the resistance of a circuit under test is higher
than 150Ω.
Notes:
• The normal voltage drop of a good silicon junction is about 0.5~0.8V.
FREQUENCY/DUTY RATIO
CAPACITANCE
CURRENT CLAMP MEASUREMENT
Range Resolution Accuracy Overload protection
0.1%~99.9% 0.1% For reference only 600Vp
9.999Hz~9.999MHz 0.001Hz~0.001MHz
±(0.1%+4)
Input range a: (DC level zero)
• ≤100kHz: ≥100mVrms≤ a ≤20Vrms
• >100kHz~1MHz: ≥200mVrms≤ a ≤20Vrms
• >1MHz: 500mVrms≤ a ≤20Vrms
• 5MHz~10MHz: 900mVrms≤ a ≤20Vrms
Note:
• Duty ratio % only applicable for measurement ≤100kHz
• During measurement of AC voltage or current, to read online frequency or duty
ratio the following input should be met:
Frequency response: ≤1kHz
Range Resolution Accuracy Overload Protection
60A DC 0.01A ±(1.0%+3) 600Vp
60A AC ±(1.2%+3)

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DC CURRENT
AC CURRENT
TEMPERATURE MEASUREMENT
Range Resolution Accuracy
oC -40~1000oC
-40~0oC
1oC
±3
>0~100oC±(1.0%+3)
>100~1000oC±(2.0%+3)
oF -40~1832oF
-40~32oF
1oF
±5
>32~212oF±(1.5%+5)
>212~1832oF±(2.5%+5)
Note:
• The K type point (Ni-Cr and Ni-Si) thermocouple in only
applicable for the measurement of temperature under
230oC/446oF.
Note:
• Frequency response: 45~1kHz
• Display : true RMS
Range Resolution Accuracy Overload Protection
600.0µA 0.1µA
±(0.7%+2)
600V DC/AC
Fuse 0.6A
Fuse 10A
6000µA 1µA
60.00mA 10µA
600.0mA 0.1mA
±(1.0%+3)
6.000A 1mA
10.00A 10mA
Range Resolution Accuracy Overload Protection
600.0µA 0.1µA
±(1.0%+3)
600V DC/AC
(<1A range) Fuse 0.6A
(>10A range) Fuse 10A
6000µA 1µA
60.00mA 10µA
600.0mA 0.1mA
±(1.2%+3)
6.000A 1mA
10.00A 10mA
Internal Fuse Check
• By using the resistance measurement function, the state of
the internal fuses can be tested.
1. Turn the range selector to Ω.
2. Connect the test leads as shown to check each fuse.

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OPERATION
Measuring DC/AC Voltage
• To measure DC/AC voltage, perform the following steps:
1. Insert the red test lead into the VΩHzoCterminal and the black test lead into
the COM terminal.
2. Turn the range selector to mV~measurement
mode and connect the test probes in parallel
with the object being measured. The measured
value shows on the display. Press REL to
switch from auto range as default to manual
range during the measurement if required.
3. When the load impedance is ~10MΩ the load
may cause measurement errors, but it is so
low it can be ignored if the circuit impedance is
under 10k.
Note:
• When a measurement has been completed,
disconnect the test probes from the circuit under test, and remove the test leads
from the input terminals.
• Do not attempt to measure voltages over 600Vrms as although a measurement
may be given, the meter may be damaged.
Measuring Resistance
• To measure the resistance, perform the following steps:
1. Insert the red test lead into the VΩHzoCterminal
and the black test lead into the COM terminal.
2. Turn the range selector to Ω. Press REL to
switch from auto range as default to manual range
during the measurement if required.
3. Connect the test probes with the object being
measured. The measured value shows on the
display.
4. If measuring low resistance the test leads will add
about 0.1Ω~0.2Ω to the reading. To obtain an
accurate reading, short the test probes and use the
REL measurement mode.
Notes:
• OL is displayed if the reading is out of range.
• Turn off all power to the circuit under test and discharge all capacitors before
connecting the meter.
• To obtain a more precise reading, you could remove the object being measured
from the circuit when measuring.
• When a measurement has been completed, disconnect the test probes from the
circuit under test, and remove the test leads from the input terminals.
• Do not exceed 60VDC or 30VAC in this mode.

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Measuring Continuity
• To measure continuity, perform the following steps:
1. Insert the red test lead into the VΩHzoC terminal and the black test lead into
the COM terminal.
2. Turn the range selector to measurement
mode and connect the test probes to the object
being measured.
3. Press SELECT to switch to continuity
measurement mode if needed.
4. The measured value shows on the display.
5. The buzzer will sound if the resistance of a
circuit under test is less than 10Ω.
6. The buzzer may sound if the resistance of a
circuit under test is between 10Ω and 150Ω.
7. The buzzer does not sound if the resistance of a
circuit under test is higher than 150Ω.
Note:
• Turn off all power to the circuit under test and discharge all capacitors before
connecting the meter.
• When a measurement has been completed, disconnect the test probes from the
circuit under test, and remove the test leads from the input terminals.
Diode Check
• Use the diode test mode to check diodes, transistors and other semiconductor
devices. In diode test mode, a current is sent through the semiconductor junction
and the voltage drop across the junction is measured.
• A good silicon junction drop is between 0.5V and 0.8V.
• To test a diode out of a circuit, perform the following
steps:
1. Insert the red test lead into the VΩHzoC terminal
and the black test lead into the COM terminal.
2. Turn the rotary switch to . Press SELECT to
switch to diode measurement mode if needed.
3. For forward voltage drop readings on any
semiconductor component, connect the red test
probe to the component’s anode and the black
test probe to the cathode.
Notes:
• Test voltage for diode check is ~3.2V.
• Turn off all power to the circuit under test and discharge all capacitors before
connecting the meter.
• When a measurement has been completed, disconnect the test probes from the
circuit under test, and remove the test leads from the input terminals.

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Duty Cycle measurement
• To measure duty cycle, perform the following steps,
1. Insert the red test lead into the terminal
and the black test lead into the COM terminal.
2. Turn the rotary switch to Hz to select duty cycle
measurement mode.
3. Connect the test probes with the object being
measured. The measured value shows on the
display.
Note:
• When a measurement has been completed, disconnect
the test probes from the circuit under test and remove
the test leads from the input terminals.
Temperature measurement
• To measure temperature, perform the following steps:
1. Insert the red Thermocouple lead into the VΩHzoC
terminal and the black lead into the COM terminal.
2. Turn the rotary switch to oCoFto select temperature
measurement mode.
3. The measured value shows on the display.
Note:
• When a measurement has been completed, disconnect
the thermocouple from the circuit under test and remove
the test leads from the input terminals.
Capacitance measurement
• To measure the resistance, perform the following steps:
1. Insert the red test lead into the VΩHzoCterminal
and the black test lead into the COM terminal.
2. Turn the range selector to , the meter and leads
will display a xed internal capacitance. Press
REL to switch to relative measurement which
will automatically deduct this value from the
measured value.
3. Connect the test probes with the object being
measured. The actual value shows on the display.
4. Several seconds may be needed to measure a high value capacitor.
Notes:
• OL is displayed if the reading is out of range.
• Turn off all power to the circuit under test and discharge all capacitors before
connecting the meter.
• When a measurement has been completed, disconnect the test probes from the
circuit under test and remove the test leads from the input terminals.
AC and DC Current measurement
• To measure current, perform the following steps,
1. Turn the rotary switch to Aand press SELECT to switch between DC
(as default) and AC RMS measurement mode.
2. Connect the red test lead to either mA or Aterminal and the black lead into
the COM terminal.

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3. Connect the test leads to the circuit to be
measured in series.
4. Alternatively connect the current clamp to the
VΩHzoC terminal and the COM terminal.
5. Turn the rotary switch to to measure up to
60A AC or DC.
6. Open the clamp jaws and pass the cable into
the clamp and close the jaws.
7. The measured value shows on the display.
Notes:
• If you do not know the approximate value to be
measured, use the higher value setting and input
connection initially.
• Never connect the meter in parallel with any
circuit.
• When measuring AC current, pressing Hz% button
will display the AC frequency/duty ratio.
• When a measurement has been completed,
disconnect the test probes from the circuit under
test and remove the test leads form the meter.
• The operating temperature must be 0ºC ~40ºC
when measuring current.
Non-contact AV Voltage sense
• To detect AC voltage or electromagnetic field, perform the following steps:
1. Turn the rotary switch to NCV.
2. Allow the front end of the meter to be close to the
object to be sensed.
3. EF is displayed if the analogue quantity of AC
voltage is detected.
4. - is displayed if the detected voltage is > critical
voltage.
5. - - - - is displayed accompanied by the sounder level
depending on the detected voltage Vd.
Note:
• Test leads are not required when the rotary control is set
to NCV.
Other Functions
• The meter will automatically power off to save the battery if no button is pressed in
15 minutes. Pressing any button will wake the meter up. The sounder will bleep 1
min prior to power off and again as it powers down.
• To switch off the auto power off, hold the SELECT button when powering on. The
sounder will bleep to inform you that auto power off is disabled. The sounder will
bleep every 15 minutes.
• Restore auto power off by turning off the meter and turning back on again.
• A valid button or rotary control selection will produce a short bleep.
• A continuous tone is emitted if the measured reading is over range for the selection
made when in the AC or DC voltage or current mode.

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INFORMATION ON WASTE DISPOSAL FOR CONSUMERS OF
ELECTRICAL & ELECTRONIC EQUIPMENT
These symbols indicate that separate collection of Waste Electrical and Electronic Equipment
(WEEE) or waste batteries is required. Do not dispose of these items with general household
waste. Separate for the treatment, recovery and recycling of the materials used. Waste batteries
can be returned to any waste battery recycling point which are provided by most battery retailers.
Contact your local authority for details of the battery and WEEE recycling schemes available in
your area.
Made in China. PR2 9PP
Man Rev 1.0
MAINTENANCE
Replacing the battery
• When the meter displays the low battery symbol, replace the
batteries immediately in order to maintain normal operation.
If the battery symbol remains on the display the meter cannot
be used until they have been replaced.
• Disconnect and remove all test probes from any live source
and the meter.
• Open the battery cover on the rear case with a screwdriver.
• Remove the old batteries and t new 1.5V AA batteries into
the battery holder.
• Replace the battery cover.
Cleaning
• Clean the meter with a clean, soft cloth.
• Do not use any chemicals, abrasives or solvents that could damage the meter.
• Clean the terminals with a mild detergent, as dirt on the terminals can affect
readings.
SPECIFICATIONS
Function Range/description
Operating Temperature: 0o~40oC (32oF~104oF)
Relative Humidity: ≤75%@ 0oC~30oC
≤50%@ 30oC~40oC
Operating ASL: 0~2000m
Battery Type: 2 off 1.5V AA
Dimensions (H x W x L): 175 x 80 x 48mm
Weight: 350g incl battery
Range: Auto
Polarity: Auto
Display: 6000 refresh 2~3 per second
DC Voltage: 0 to 600V
AC Voltage true RMS: 0 to 600V