Tenma 72-7780 User manual

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TrueRMSDigitalMultimeter
Model:72‐7780
UserManual
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I. Overview
72‐2800isaprofessionalhandheldtrueRMSmultimeterwithwidescopeof
application.Itisasafe,stableandreliablemeasurementdeviceforAC/DC,resistance,
diode,continuity,capacitance,frequency,NCVmeasurementetc.
II. UnpackingInspection
Openthepackageboxandtakeoutthedevice.Pleasecheckwhetherthefollowing
itemsaredeficientordamagedandcontactyoursupplierimmediatelyiftheyare.
•Usermanual‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐1pc
•Testleads‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐1pair
•K‐typethermocouple‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐1pc
•Optionalcurrentclamp
III. Safetyinformation
SafetyStandards
•EN61010‐1:2010
•CATIII600V,doubleinsulationstandard,overvoltagestandard,andRoHS,
pollutiongradeII
Pleasereadandcomplywiththesafetyinformationcarefully,ortheprotection
providedbythedevicemaybeimpaired.
1. Donotusethedeviceiftherearcoverisnotcovereduporitwillposeashock
hazard
2. Donotusethedeviceifthedeviceortestleadsappeardamagedorifyou
suspectthatthedeviceisnotoperatingproperly.Payparticularattentiontothe
insulationlayers.
3. Toavoidfalsereading,replacethebatterywhenthebatteryindicator
appears.
4. Functionaldialshouldbeswitchedtoproperposition.
5. Neverinputvoltageandcurrentexceedingthevaluelistedonthedevice.
6. Donotswitchthefunctionaldialduringmeasuring.
7. Aftereachmeasure,disconnectthetestleadswiththecircuit.Formeasuring
current,switchoffthepowersupplybeforetestleadsdisconnection,especially
importantformeasuringlargecurrent.
8. Usecautiontomeasurevoltage>DC60VorAC30Vrms.
9. Donotuseorstorethedeviceinhightemperature,highhumidity,flammable,
explosiveorstrongmagneticfieldenvironments.
10. Donotchangetheinternalcircuitofthedeviceinordertoavoidthedamageto
thedeviceandusers.
11. Usedampclothtocleanthecase;donotusedetergentcontainingsolventsor
abradants.
IV. Symbols
Lowbattery
Buzzerindicator

Diode
AC/DC
Warning
Grounding
Currentclamp
Doubleinsulation
ComplywithEuropeanUnionDirectives
V. Generalspecifications
1) Maxvoltagebetweeninputterminalsandearthgrounding:SeeTechnical
Specifications
2) FuseType:
10AJack:F10AH600VFuse(Φ6x25)mm
mA/μAJack:F600mAH600VFuse(Φ6x32)mm
3) MaxDisplayValue:
Capacitancemeasurement:9999
Frequencymeasurement:9999
Othermeasurement:6000
DutyRatio：1~99.9%
Diode:3.2V
Others:
1) Range:Auto/Manual
2) Polarity:Auto
3) Displayupdates2~3timesforeverysecond.OverrangeIndicator:“OL”
4) Operatingtemperature:0˚C~40˚C(32˚F~104˚F)
Storagetemperature:‐10˚C~50˚C(14˚F~122˚F)
Relativehumidity:≤75%at0˚C~30˚C;≤50%at30˚C~40˚C
5) Operatingaltitude:0~2000m
6) Batterytype:AAR6P1.5V×2
7) Lowpowerindicator:
8) Dimension:175mm×80mm×48.5mm
9) Weight:350g(batteriesincluded)
10) Electromagneticcompatibility:
RF≤1V/m,overallaccuracy=specifiedaccuracy+5%ofrange.
RF>1V/m,nospecifiedcalculation.
VI. Structure(seefigure1)
1/Protectivecase
2/Displayscreen
3/4/7Functionalbuttons
5/Functionaldial
6/Inputjacks
VII. Display

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SymbolIndication
Datahold
━Negativevalue
AC/DCACorDCmeasurement
MAX/MINMaximumorminimumreading
Lowpower
AutoRangeAutorangeselection
Diodemeasurement
Continuitymeasurement
Relativemeasurement
Ω、kΩ、MΩ Unitofresistance
Hz、kHz、MHzUnitoffrequency
%Unitofdutyratio
mV、VUnitofvoltage
μA、mA、AUnitofcurrent
nF、μF、mFUnitofcapacitance
˚
CCelsiusdegree
˚
FFahrenheitdegree
NCVNon‐contactvoltage
Autoshutdown
Currentclamp
VIII. Functionaldialandbuttons
PositionNote
V、V、mVAC/DCvoltage
Ω Resistance
Diode
Continuity
Capacitance
HzFrequency
%Dutyratio
˚C/˚FTemperature
μAmA AAC/DCcurrent
60A AC/DCcurrentclamp

NCVNon‐contactvoltage
OFFshutdown
Buttons：
RANGE：Switchtherangemodetoauto/manualandthencyclethroughallranges.To
exitauto/manualmode,pressthebuttonfor2secondsorswitchthefunctionaldial.
(OnlyforV,Ω,I measurement)
MAX/MIN：StartsandstopsMax/Minrecording.Toexitthismode,pressthebutton
for2secondsorswitchthefunctionaldial.(OnlyforV,Ω,I and˚C/˚F
measurement)
REL：Savethefirstreadingasreferencevalue.Thesecondreading=second
measurementvalue‐referencevalue.Toexithismode,pressthebuttonfor2seconds.
(OnlyforV,Ω,I and˚C/˚Fandmeasurement);whenmeasuringcapacitance,
RELbuttonisonlyusedforeliminatingintrinsicvalue.
Hz/%：WhenmeasuringACvoltage/current,pressthebuttontocyclethrough
frequencyanddutyratiomeasurement.
SELECT：Selectfunctions.UnderACmodes,longpressthebuttonuntilUFCappears
toenterVFCmeasurementmodeandmeasurethevariablefrequencyvoltage.Long
pressgaintoexitVFCmeasurementmode.
HOLD：Pressthebuttononcetoholdthereading.Pressagaintounlockthereading
andentergeneralmeasurementmodes.
IX. Operationinstructions
Toavoidfalsereading,replacethebatteryifthebatterylowpowersymbol
appears.Alsopayspecialattentiontothewarningsignbesidesthetestlead
housing,indicatingthatthetestedvoltageorcurrentmustnotexceedthevalues
listedonthedevice.
1.AC/DCvoltagemeasurement(seeFigure3)
1) Connecttestleadswiththeloadinparallel.
2) Wheninputimpedanceabout10MΩ,thereis
measurementerrors.Inputimpedance≤10kΩ,
measurementerrorscanbeignored(≤0.1%)
Notes:
•Donotmeasurevoltageover600Vrms,oritmayexpose
userstoelectricshockanddamagethedevice.
•Pleasepayextraattentionwhenmeasuringhighvoltagein
ordertoavoidelectricshock.
2.Resistancemeasurement(seefigure4a)
Connecttestleadswiththeresistanceinparallel.
Warnings:
•Iftheresistorisopenorovertherange,the“OL”symbol
willbedisplayedonthescreen.
•Beforemeasuringresistance,switchoffthepowersupply
ofthecircuit,andfullydischargeallcapacitors.
•Whenmeasuringlowresistance,thetestleadswillproduce
0.1Ω~0.2Ωmeasurementerror.Toobtainaccurate

measurement,shortthetestleadsanduseRELfunction.
•Iftheresistancewhenshortedismorethan0.5Ω,pleasecheckiftestleadsare
loosenedordamaged.
•Whenmeasuringhighresistanceabove60MΩ,itisnormaltotakeafewseconds
tosteadythereadings.
•Resistancemeasurementcanbeusedtoinspectdevice’sinternalfuses.(see
figure4b)
•DonotinputvoltageoverDC60VorAC30V.
3.Continuitymeasurement(seefigure5)
Iftheresistancebeingmeasuredisover150Ω,circuitisinopen
status,buzzerdoesnotgooff.Iftheresistancelessthan10Ω,
circuitisingoodconductionstatus,buzzerwillcontinuouslygooff.
Note:
•Toavoiddamagetothedevice,beforemeasuringcontinuity,
switchoffallpowersuppliesandfullydischargeallcapacitors.
•DonotinputvoltageoverDC60VorAC30V.
4.Diodemeasurement(seefigure6)
“OL”symbolappearswhenthediodeisopenorpolarityis
reversed.
ForsiliconPNjunction,normalvalue:500~800mV(0.5~0.8V).
Notes:
•Switchoffthepowersupplytothecircuit,andfullydischarge
allcapacitors
•Voltagefortestingdiodeisabout3.1V.
•DonotinputvoltageoverDC60VorAC30V.
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5.Capacitancemeasurement(seefigure7)
Whenthereisnoinput,thedevicedisplaysafixedvalue
(intrinsiccapacitance).Forsmallcapacitance
measurement,toensuremeasurementaccuracy,the
measuredvaluemustbesubtractedfromintrinsic
capacitance.Oruserscanmeasuresmallcapacity
capacitorswithrelativemeasurementfunction(REL)(the
devicewillautomaticallysubtracttheintrinsic

capacitance)
Notes:
•Ifthetestedcapacitorisshortedoritscapacityis
overthespecifiedrange“OL”symbolwillbe
displayedonthescreen.
•Whenmeasuringlargecapacitors,itmaytakeafew
secondstoobtainsteadyreadings.
•Beforemeasuringcapacitors(especiallyforhigh
voltagecapacitors),pleasefullydischargethem.
6.Frequency/Dutyratiomeasurement(seefigure8)
Atthefrequencyposition,presstheHz/%toselect
frequency/dutyratiomeasurementmode.
Notes:
•DonotinputvoltageoverDC60VorAC30V.
7.Temperaturemeasurement(seefigure9)
Turnonthedevice,after“OL”symbolappears,insert
K‐thermocoupleintothedevice.
Note:
OnlyK‐typethermocoupleisapplicable.Themeasured
temperatureshouldbelessthan230˚C/446˚F
(˚F=˚C*1.8+32)
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8.AC/DCcurrentmeasurement(seefigure10)
Connecttestleadswiththetestedcircuitinseries.
ReadingsunderthisACmeasurementistrueRMS.
Notes:
•Beforemeasuring,switchoffthepowersupplyof
thecircuit.
•Iftherangeofthemeasuredcurrentisunknown,
selectthemaximumrangeandthenaccordingly
reduce.
•Therearefusesinside10AjackandmA/μAjack.Do
notconnectthetestleadswithanycircuitsin
parallel.
•Ifthetestedcurrentisover5A,eachmeasurement
timeshouldbelessthan10secondsandthenext
testshouldbeafter15minutes.
•WhenmeasuringACcurrent,pressHz/%buttonto
displayACfrequencyordutyratio.
•60AACandDCcurrentclampmeasurement(see
figure11)
Connectasshownwiththeattachedcurrentclamp.
9.NCVmeasurement(seefigure12)
1）SwitchthedialtoNCVposition

2）Placethedevicenearthemeasuredobject.
“‐“symbolindicatestheintensityoftheelectric
field.More“‐“andthehigherthebuzzerfrequency,
thehighertheelectricfieldintensity.
3）Intensityofelectricfield
*"EF":0~50mV
*"‐":50~100mV
*"‐‐":100~150mV
*"‐‐‐":150~200mV
*"‐‐‐‐":>200mV
.Notes:
TestleadsarenotrequiredforNCVmeasurement.

10.Others
•Thedeviceentersmeasurementstatusin2secondsafterstartup.Restartthe
device,”ErrE”appears.
•Thedeviceautomaticallyshutsdownifthereisnooperationfor15minutes.
Youcanwakeupthedevicebypressinganykey.Todisableautoshutdown,
switchthedialtoOFFposition,longpressSELETEbuttonandturnonthedevice.
symbolwilldisappearwithonelongbeep.Recovertheauto‐offfunctionby
restartingthedevice.
•Buzzernotification
1)Inputvoltage≥600V(AC/DC),buzzerwillcontinuouslybeepindicatingmeasure
rangeisatlimit
2)Inputcurrent>10A(AC/DC),buzzerwillcontinuouslybeepindicatingmeasure
rangeisatlimit
•Lowpowerwarnings:Voltageofthebattery<2.4V,symbolappears,the
devicecanstillbeused.Ifvoltageislowerthan2.2V,thedevicecannotworkand
thesymboldisappearsafterstartup.
•Thescreenbacklightcannotworkifbatteryvoltagelessthan2.6V.
X. Technicalspecification
Accuracy:±(%ofreading+numericalvalueinleastsignificantdigitslot),1Year
Warranty
Ambienttemperature:23˚C±5˚C(73.4˚F±9˚F)
Ambienthumidity:≤75%RH
1.DCvoltage
RangeResoluti
onAccuracy
60.00mV*0.01mV±(0.5%+2)
600.0mV**0.1mV
6.000V0.001V
±(0.7%+3)
60.00V0.01V
600.0V0.1V
600V1V

Inputimpedance:about10MΩ.
ResultsmightbeunstableatmVrangewhennoloadisconnected.Thevalue
becomesstableoncetheloadisconnected.Leastsignificantdigit≤±3
Maxinputvoltage:±600V,whenthevoltage≥600V,"OL”symbolappearsandthe
buzzergoesoff.”

2.ACvoltage
RangeResolutionAccuracy
60.00mV0.01mV±(1.0%+3)
600.0mV0.1mV
6.000V0.001V
±(0.8%+3)
60.00V0.01V
600.0V0.1V
600V1V±(1.0%+3)
VFC200.0V~600V0.1/1V±(4.0%+3)
Inputimpedance:about10MΩ
DisplaytrueRMS.Frequencyresponse:45Hz~1KHz(LPF45~400Hz)
Accuracyguaranteerange:5‐100%oftherange,shortedcircuitallowsleast
significantdigit≤10 
CrestfactoratMaxrange=3.0(excluding600Vrange,crestfactor=1.5)
Maxinputvoltage:600Vrms
3.Resistancemeasurement.
RangeResolutionAccuracy
600.0Ω 0.1Ω ±(1.0%+2)
6.000kΩ 0.001kΩ
±(0.8%+2)60.00kΩ 0.01kΩ
600.0kΩ 0.1kΩ
6.000MΩ 0.001MΩ ±(1.2%+3)
60.00MΩ 0.01MΩ ±(1.5%+5)
Measurementresult=readingofresistor–readingofshortedtestleads
Opencircuitvoltage=1V(Current=0.4mA)
Overloadprotection:600V‐PTC
4.Continuity,Diode
PositionResolutionRemark
0.1Ω
SetValue:
Opencircuit:resistance≥150Ω,nobeep.
Well‐connectedcircuit:resistance≤10Ω,continuous
beeps.
0.001VOpencircuitvoltage:3.2V
SiliconPNjunctionvoltage:0.5~0.8V.
Overloadprotection:600V‐PTC

5.Capacitance
RangeResolutionAccuracy
9.999nF0.001nFRELmode：±(4%+10)
99.99nF~999.9μF0.01nF~0.1μF±(4%+5)
9.999mF~99.99mF0.001mF~0.01mF±10%
Overloadprotection:600V‐PTC
Testcapacitance≤100nF,adaptRELmode.
6.Frequency/Dutyratio
Range ResolutionAccuracy
9.999Hz~9.999MHz0.001Hz~0.001MHz±(0.1%+4)
0.1%~99.9%0.1%Onlyforreference
Overloadprotection:600V‐PTC
Inputrange:(DClevel=0)
≤100kHz:100mVrms≤a≤20Vrms
>100kHz~1MHz:200mVrms≤a≤20Vrms
>1MHz:500mVrms≤a≤20Vrms
>5MHz~10MHz:1Vrms≤a≤20Vrms
Dutyratio%：Onlyforfrequencymeasurement≤100kHz
Notes：WhenmeasuringACvoltageorcurrent,followingconditionsshouldbe
satisfied:
Frequencyresponse≤1kHz
ACvoltage:mVposition≥100mV;Vposition≥Range×6%
ACcurrent:inputrange:4000/6000μA,400/600mA,10A:A≥range×6%
400/600μA,40/60mA,4/6A:A≥range×60%
7.Temperature
RangeResolutionAccuracy
˚C˚‐40~1000˚C
‐40~0˚C
1˚C
±3
>0~100˚C±(1.0%+3)
>100~1000˚C±(2.0%+3)
˚F‐40~1832˚F
‐40~32˚F
1˚F
±5
>32~212˚F±(1.5%+5)
>212~1832˚F±(2.5%+5)
Overloadprotection:600V‐PTC
•K‐typethermocoupleisonlyapplicablefortemperaturelessthan250˚C/482˚F.
8.DCcurrent
RangeResolution Accuracy
μA600.0μA0.1μA
±(0.7%+2)
6000μA1μA
mA60.00mA0.01mA
600.0mA0.1mA
A6.000A0.001A±(1.0%+3)
10.00A0.01A
•Overloadprotection:

μAmArange:F1Fuse(φ6×32)mm FF600mAH600V
10Arange:F2Fuse(φ6×25)mm FF10AH600V
9.ACcurrent
RangeResolutionAccuracy
μA600.0μA0.1μA
±(1.0+3)
6000μA1μA
mA60.00mA10μA
600.0mA0.1mA
A6.000A1mA±(1.2%+3)
10.00A10mA
Frequencyresponse:45~1kHz
Display:trueRMS
Accuracyguaranteerange:5‐100%oftherange,shortedcircuitallowsleast
significantdigit≤2
CrestfactoratMaxrange=3.0
Overloadprotection:(similartoDCcurrent)
10.Currentclampmeasurement(60A)
RangeResolutionAccuracy
60ADC0.01A±(1.0+3)
60AAC±(1.2+3)
Overloadprotection:(similartoDCcurrent)
XI. Maintenance
Warning:Beforeopeningtherearcover,switchoffthepowersupply(remove
testleadsfromtheinputterminalandthecircuit).
1.Generalmaintenance
1)Cleanthecasewithadampclothanddetergent.Donotuseabradantsor
solvents
2)Ifthereisanymalfunction,stopusingthedeviceandsendittomaintenance.
3)Themaintenanceandservicemustbeimplementedbyqualifiedprofessionalsor
designateddepartments.

2.Replacements(seeFigure13)
Batteryreplacement:
Toavoidfalsereading,replacethebatterywhenthe
batteryindicatorappears.
BatterySpecification:AA1.5Vx2
1)Switchthedialto“OFF“positionandremovethe
testleadsfromtheinputterminal.
2)Takeofftheprotectivecase.Loosenthescrewon
batterycover;removethecovertoreplacethe
battery.Pleaseidentifythepositiveandnegative
pole.

Fusereplacement:
1)Switchthedialto“OFF“positionandremovetheteatleadsfromtheinput
terminal
2)Loosenthebothscrewsontherearcover,andthenremovetherearcoverto
replacethefuse
Fusespecification
F1Fuseφ6×32mmFF600mAH600V
F2Fuseφ6×25mmFF10AH600V





TenmaTestEquipment
405S.PioneerBlvd.
Springboro,Oh
