Uni-Trend UT81B multimeter
Contents
1. 23 mA Range Measurement 24 10A Range Measurement 25 Resistance Measurement _ _ _ 27 Diode Test 29 Continuity Test _ _ _ _ __ __ ___ __ __ 31 Frequency Duty Cycle Measurement 33 Capacitance Measurement C 35 Fuse Replacement _ _ _ _ _ _ 89 Battery Replacement Overview This Operating Manual covers information on safety and cautions Please read the relevant information carefully and observe all the Warnings and Notes strictly A Warning To avoid electric shock or personal injury read the Safety Information and Rules for Safe Operation carefully before using the Meter Scope Digital Multimeter UT81A B hereafter referred to as the Meter is a 3999 counts and 3 3 4 digits adopting digital control techique with both waveform and multimeter all in one Scope mode is a complete intelligent measurement system including signal input sampling data process auto search and waveform save and recall It has 6 Model UT81A B OPERATING MANUAL Chapter 1 Before You2. Range Under scope mode Press Range button to switch between DC and AC measurement Time Under scope mode press Time button to set the X axis of time base Trig Under scope mode press Trig button to change the trigger mode Auto In multimeter mode Press Auto button to enter autoranging mode when measuring resistance voltage and current This button is invalid when measuring capacitance diode continuity buzzer and capacitance In scope mode Press Auto button to set the amplitude and time base to auto 13 Table 2 2 Functional Buttons Buttons Description Mode To switch between waveform display scope mode and digital reading multimeter mode This button is only valid when under voltage frequency currents mode Set Press Set button to set the auto power off backlight contrast and beep Save Call Under scope mode press Save Cal to store and recall data Hold Press Hold button to enter or exit hold mode 14 Model UT81A B OPERATING MANUAL Model UT81A B OPERATING MANUAL Introduction Chapter 3 explains how to make measurements You could turn the Meter off by turning to OFF position or set up the sleep mode from 1 30 minutes Please must ensure the Meter is not under sleep mode if you turn the Meter on but without displ
3. Trig A Trig Auto Norm Shot Slop Rrise Fall F1 F2 F3 F4 F1 move the trigger level up F2 move the trigger level down F3 select the trigger mode auto normal or single F4 slope adjustment rise or fall iv Waveform data save and recall Press Save Call button under scope mode the corresponding functional buttons Save Call A 1 wv Enter F1 F2 F3 F4 F1 save or recall F2 and F3 select location location from 0 9 total 10 location F4 confirm When saving the data it will overwrite the current data in the location no matter that location has data or not If you recall the location has no data the meter will appear error message you need to press HOLD button to continue measurement If you recall the location has data it will save the current setting and display the data the LCD top left shows REV to indicate recalling mode is on Press HOLD button to return to working mode and continue measurement You could continue recalling under recall mode or save the data Recall mode can be used under any scope mode For example it is possible to recall the waveform or data saved from voltage or frequency mode when the meter is under current measurement mode Recall mode can be worked under any waveform mode For example the Meter is at current mode but recalling the waveform or data which are saved under voltage or frequency mode Th
4. and interval more than 15 minutes 47 Model UT81A B OPERATING MANUAL D AC Current i Under Multimeter mode Range Resolution Accuracy Overload Protection 400uA 0 1uA eae 4000uA 14A F0 5AH 250V 05x20mm 40mA 10uA 2 400mA 100A 8 4A 1mA din F10AH 250V 95x20mm 10A 10mA 29799 Continuous measurement lt 10 seconds and interval more than 15 minutes Remarks Frequency Response 40Hz 400Hz Displays effective value of sine wave mean value response 48 Model UT81A B OPERATING MANUAL ii Under Scope mode The specification is same as Di Under Multimeter mode On the top right corner of the display shows the accuracy of the frequency which is around 2 When the LCD displays 1 10 period waveform the reading is valid otherwise the Meter displays E Resistance Range Resolution Accuracy Overload Protection 4000 0 10 1 2 5 4kQ 10 40kQ 10Q 1 5 400kQ 1000 250VDC or AC rms 4MQ 1kQ 1 2 5 40MQ 10kQ 1 5 5 Diode Test Range Resolution Overload Protection Remarks Jr 1mV 250V DC or AC A good silicon junction drops between 0 5V and 0 8V 49 G Continuity Test Test Model UT81A B OPERATING MANUAL Range Resolution Overload Protection Remarks The buzzer sounds when the test resistance 0 10 250V DC or AC 100 1 i or The buzzer does not sound when the te
5. Rang Figure 3 2 Voltages Measurement F1 F2 F4 F1 toggle between AC or DC F2 relative mode REL will be displayed at the right bottom of the LCD when it is on F3 select a range up F4 select a range down Note After changing the measurement mode the autoranging will be off automatically and the AUTO will be disappeared at the bottom left of the LCD When voltage measurement has been completed disconnect the connection between the testing leads and the circuit under test and remove testing leads away from the input terminals of the Meter 21 Measuring Currents A Warning If the fuse burns out during measurement the Meter may be damaged or the operator himself may be hurt To avoid possible damage to the Meter or to the equipment under test check the Meter s fuses before measuring current Use proper terminals function and range for the measurement Never place the testing leads in parallel with any circuit or component when the leads are plugged into the current terminals Turn off power to the circuit before test leads are connected in series to the return circuit to be tested 22 Model UT81A B OPERATING MANUAL Model UT81A B OPERATING MANUAL Range Measurement 1 Insert the red test lead into the umA terminal and To measure ACuA or DCA currents set up the black test lead into the COM t
6. fuse by gently prying one end loose then take out the fuse from its bracket Install ONLY replacement fuses with the identical type and specification as follows and make sure the fuse is fixed firmly in the bracket Fuse 1 F0 5AH 250V 95 x 20mm Fuse 2 F10AH 250V 95 x 20mm Rejoin the case bottom and case top battery compartment and case bottom and install the 5 Screws Replacement of the fuses is seldom required Burning of a fuse always results from improper operation 39 C Replacing the Battery Figure 5 2 Battery Replacement 40 Model UT81A B OPERATING MANUAL AN Warning To avoid false readings which could lead to possible electric shock or personal injury replace the battery as soon as the battery indicator f appears Make sure the test leads are disconnected from the circuit being tested before opening the case bottom Follow Figure 5 2 and proceed as follows to replace the battery Turn the rotary switch to OFF and remove all connections from the terminals Remove the screw from the battery compartment and separate the battery compartment from the case bottom Replace with 4 pieces new 1 5V R6P batteries Rejoin the case bottom and battery compartment and reinstall the screw Model UT81A B OPERATING MANUAL Safety and Compliances Maximum Voltage between any Terminal and Chapter 6 Specifications Refer to different range input protection voltage
7. Dongguan City Guang Dong Province China Postal Code 523 925 Headquarters Uni Trend Group Limited Rm901 9 F Nanyang Plaza 57 Hung To Road Kwun Tong Kowloon Hong Kong Tel 852 2950 9168 Fax 852 2950 9303 Email info uni trend com http www uni trend com 53
8. Grounding Certification CE Compliances IEC 61010 CAT II 1000V CAT III 600V overvoltage and double insulation standard A Fused Protection for mA input terminal A Fused Protection for 10A input terminal F0 5AH 250V 85x20mm F10AH 250V 95x20mm 41 Physical Specifications Model UT81A B OPERATING MANUAL Display LCD Digital 3999 counts on display updates 2 3 times second Operating Temperature 0 C 40 C 32 F 104 F Storage Temperature 10 C 50 C 14 F 122 F Relative Humidity lt 75 9 0 C 40 C lt 0 9 10 C 50 C Altitude Operating 2000m Storage 10000m Battery Type 1 5V R6 x 4 Batteries or Power adaptor Check carefully about the working voltage of power adaptor before use Electromagnetic Compatibility In a radio field of 1 V m below Overall Accuracy Specified Accuracy 5 of Range In a radio field of 1 V m above No assigned accuracy is specified Dimensions H x W x L 200 x 100 x 48mm Weight Approx 498g including battery 42 Model UT81A B OPERATING MANUAL General Specifications Digital Multimeter Range When it is under Multimeter mode you could select either auto or manual ranging Polarity Auto negative polarity displays Overloading Display OL Battery Deficiency Display Fi General Specifications Scope Display 160 x 160 Monochr
9. LINII T Model UT81A B OPERATING MANUAL Model UT81A B OPERATING MANUAL Table of Contents Chapter Title Page 1 Before You Start _ _ _ _ __ __ ___ __ ___ ___ __ __ __6 amp Overview Unpacking We Safety Information 8 Rules For Safe Operation 8 International Electrical Symbols 10 2 Using The Testing Tool 11 Reading the screen The Meter Structure _ _ _ _ __ __ _ _ 12 Functional Buttons 13 3 Making Measurements _ _ _ _ __ __ __ __ __ 15 A Scope Mode s i Setting up the Sleep Mode Contrast Beep 15 ii ACV DCV Hz ACV and DCA dii 7 iii Trigger function 19 iv Waveform data save and recall 19 B Digital Multimeter Mode _ c cll A20 i Mea
10. Start bandwidth UT81A 2MHz UT81B 8MHz real time sample rate 40MS s with peak rate sampling process can catch up pulse industrial signal It can measure AC DC engine transducer circuit control UPS and industrial equipments It is an ideal tools in professional repairing industries Digital Multimeter mode can measure AC voltage and current DC voltage and current Resistance Capacitance Frequency Duty Cycle Diodes and Continuity Model UT81A B OPERATING MANUAL Unpacking Inspection Open the package case and take out the Meter Check the items shown on Table 1 1 carefully to see any missing or damaged part Table 1 1 Unpacking Inspection Item Description Qty 1 English Operating Manual 1 piece 2 USB interface cable 1 piece 3 CD ROM Installation Guide amp Computer Interface Software 1 piece 4 Test Lead 1 pair 5 Alligator Clip 1 piece 6 Power Adaptor 1 piece 7 1 5V Batteries R6 4 pieces 8 Carrying bag 1 piece 9 Scope Probe available at extra cost 1 piece 10 BNC probe available at extra cost 1 piece In the event you find any missing or damage please contact your dealer immediately Safety Information This Meter complies with the standards IEC61010 safety measurement requirement in pollution degree 2 overvoltage category CAT II 1000V CAT III 600V and double insulation CAT II Local level appliance PORTABLE EQUIPMENT etc with smaller transient overvoltages th
11. act the internal distributed capacitor value to maintain the accuracy To improve the accuracy press F2 REL with the test leads open to subtract the residual capacitance of the Meter and the test leads It is recommended to use as short as test lead carrying out measurement to reduce the effect of internal distributed capacitor Model UT81A B OPERATING MANUAL When measuring capacitance the corresponding functional buttons Capacity REL F1 F2 F2 relative mode Note Capacitors larger than 10HF take longer time If the tested capacitor has polarity connect the red test lead to positive side and black test lead to negative side When capacitance measurement has been completed disconnect the connection between the testing leads and the circuit under test and remove the test leads away from the input terminals of the Meter Model UT81A B OPERATING MANUAL Chapter 4 Using Software When using the Software please refer to the Installation Guide of the included CD ROM 37 This chapter provides basic maintenance information including battery and fuse replacement instruction A Warning Do not attempt to repair or service your Meter unless you are qualified to do so and have the relevant calibration performance test and service information A General Service Periodically wipe the case with a damp cloth and mild detergent Do not use abrasives or solvents l To clean the term
12. an CAT CAT Ill Distribution level fixed installation with smaller transient overvoltage than CAT IV Use the Meter only as specified in this operating manual otherwise the protection provided by the Meter may be impaired In this manual a Warning identifies conditions and actions that may pose hazards to the user or may damage the Meter or the equipment under test A Note identifies the information that user should pay attention to Model UT81A B OPERATING MANUAL International electrical symbols used on the Meter and in this Operating Manual are explained on page 10 Rules For Safe Operation A Warning To avoid possible electric shock or personal injury and to avoid possible damage to the Meter or to the equipment under test adhere to the following rules Before using the Meter inspect the case Do not use the Meter if it is damaged or the case or part of the case is removed Look for cracks or missing plastic Pay attention to the insulation around the connectors Inspect the test leads for damaged insulation or exposed metal Check the test leads for continuity Replace damaged test leads with identical model number or electrical specifications before using the Meter Do apply more than the 1000V rms between any terminal and grounding to avoid electric Model UT81A B OPERATING MANUAL shock or damages to the Meter The rotary switch should be placed in the right position and no any
13. ay To avoid false readings which could lead to possible electric shock or personal injury replace the battery as soon as the battery indicator appears A Scope Mode The LCD top right part display RUN HLD REV The LCD top right corner has battery icon to indicate when the battery is lower than 5V Under scope mode both reading and waveform will be displayed Chapter 3 Making Measurement i Setting up Sleep Mode Contrast Beep Based on the working environment to set up sleep mode contrast beep Press Set button to set the auto power off display backlight contrast and beep Auto off Bk Light Contrast F1 F2 F3 F4 F1 Set auto power off time Auto off A 15 ENTER F1 F2 F3 F4 The time level is from OFF 1 to 30 minutes Press F4 to confirm save and return Press functional button to exit and the setting remains unchanged 15 F2 Set the Display Backlight BK Light A 15 v ENTER F1 F2 F3 F4 The brightness level from 0 to 31 Press F4 to confirm save and return Press functional buttons to exit the setting is kept but will not save The setting will be lost after power off F3 Set the LCD contrast Contrast A 15 v ENTER F1 F2 F3 F4 The contrast level from 0 to 31 Press F4 to confirm save and return Press functional buttons to exit the s
14. changeover of range shall be made during measurement is conducted to prevent damage of the Meter When the Meter working at an effective voltage over 60V in DC or 42V rms in AC special care should be taken for there is danger of electric shock Use the proper terminals function and range for your measurements Do not use or store the Meter in an environment of high temperature humidity explosive inflammable and strong magnetic field The performance of the Meter may deteriorate after dampened When using the test leads keep your fingers behind the finger guards Disconnect circuit power and discharge all high voltage capacitors before testing resistance continuity diodes Before measuring current check the Meter s fuses and turn off power to the circuit before connecting the Meter to the circuit Replace the battery as soon as the baitery indicator Ll appears With a low battery the Meter might produce false readings that can lead to electric shock and personal injury When servicing the Meter use only the same model number or identical electrical specifications replacement parts The internal circuit of the Meter shall not be altered at will to avoid damage of the Meter and any accident Soft cloth and mild detergent should be used to clean the surface of the Meter when servicing No abrasive and solvent should be used to prevent the surface of the Meter from corrosion damage and accident The Meter is suitabl
15. ctional buttons Freq Duty F1 F1 toggle between frequency and duty cycle 33 Note The requirement of Input amplitude a is as follows When 1MHz 300 mV lt S a lt 30Vrms 21MHz 600 mV lt a lt 5Vrms Itis normal to have few seconds run time when switch from other functions to these functions When Hz or duty cycle measurement has been completed disconnect the connection between the testing leads and the circuit under test and remove the test leads away from the input terminals 34 Model UT81A B OPERATING MANUAL Model UT81A B OPERATING MANUAL vii Measuring Capacitance A Warning To ensure accuracy the Meier inside is discharged against the tested capacitor To avoid damage to the Meter or to the equipment under test disconnect circuit power and discharge all high voltage capacitors before measuring capacitance To measure capacitance set up the Meter as shown in Figure 3 10 and proceed as follows SCOPE COM val A 9 9 Figure 3 10 Measuring Capacitance 35 36 Insert the red test lead into 4 theterminal and the black test lead into the COM terminal Set the rotary switch to 4 measurement mode the Meter may display a fixed reading which is a internal distributed capacitor value For testing less than 40nF capacitor the tested value must subtr
16. e AAA 46 B AC Voltage G C DC Current 47 D AC Current A _ _ _ _ _ _ 4 E R sistance eg our us 49 F Diode Test _ _ _ _ _ __ ___ __ __ _________ 49 Continuity Test 50 Model UT81A B OPERATING MANUAL Table of Contents Chapter Title Page H Frequency and Duty Cycle _ _ _ __ __ B I Capacitance s ee eoe ue ios oe 51 Table 1 1 1 2 2 1 2 2 Model UT81A B OPERATING MANUAL List of Tables Title Page Unpacking Inspection C International Electrical Symbols o 10 Reading the Screen _ _ _ _ ___ ___ ___ __ __ __ __ 11 Functional Bittons 2 2 5 ee 8 Model UT81A B OPERATING MANUAL List of Tables Title Page Meter Structure 42 Functional Buttons e 18 Waveform Display _ _ _ _ _ __ __ ___ 17 Voltages Measurement 9 uA Range Measurement
17. e Meter must 19 be returned to working mode to carry out measurement Remarks In order to have more accurate waveform user can buy an optional BNC probe and scope probe to decrease signal attenuates The scope probe directly connect to the BNC probe When measuring voltage and frequency signal connect the BNC black probe to the COM input terminal and the red probe to the voltage terminal When measuring current signal connect BNC black probe to the COM terminal and the red probe to mA terminal Don t connect the BNC probe to the 10A terminal 20 Model UT81A B OPERATING MANUAL B Digital Multimeter Mode i Measuring Voltages A Warning To avoid harms to you or damages to the Meter from electric shock please do not attempt to measure voltages higher than DC 1000V AC 750V although readings may be obtained To measure voltages set up the Meter as Figure 3 2 and do the following 1 Insert the red test lead into the V terminal and the black test lead into the COM terminal 2 Set the rotary switch to V 3 Connect test leads across with the object being measured 4 The measured value shows on the display 5 Press MODE button to toggle between Multimeter mode and Scope mode 6 Press F1 to toggle between AC and DC voltage measurement Model UT81A B OPERATING MANUAL When measuring voltage the corresponding functional buttons AC Rang A
18. e a time base BK Light Display backlight BASE gt Waveform moves right BEEP Beeper on and off BASE lt Waveform moves left ENTER Confirm TRIG A Trigger moves up A Increase TRIG VW Trigger moves down v Decrease SLOP Trigger slope adjustment MOVEA Waveform moves up AUTO Auto trigger mode MOVE v Waveform moves down NORM Normal trigger mode RANGA Increase a range SHOT Single trigger mode 11 The Meter Structure The Figure 2 1 shows the Meter structure 12 USB Terminals LCD Display Functional Buttons Rotary Switch Power adaptor Input Terminals 10A Input Terminal MAHA Input Terminals COM Input Terminal Other Input Terminals Model UT81A B OPERATING MANUAL Ca f eee ive rj Am 1 SET SAVEICALL i Voro BAS per Hze l e MAS ESA vee ae 4 em or SCOPE COM VQH2 gt t A eH Figure 2 1 Meter Structure Model UT81A B OPERATING MANUAL Functional Buttons The buttons activate features that augment the function selected with the rotary switch The buttons are shown in Table 2 2 TIME TRIG AUTO m Figure 2 2 Functional Buttons Table 2 2 Functional Buttons Buttons Description F1 F2 Software functional buttons details F3 and F4 please refer to the below
19. e for indoor use Turn the Meter off when it is not in us e and take out the battery when not using for a long time Constantly check the baitery as it may leak when it has been using for some time replace the battery as soon as leaking appears A leaking battery will damage the Meter 9 10 Model UT81A B OPERATING MANUAL Under the influence of Radiated Radio Frequency International Electrical Symbols Electromagnetic Field phenomenon the captioned model have a 20 measurement error it will be back to normal when the interference is removed Symbols used on the Meter and in this manual are explained in Table1 2 Table 1 2 International Electrical Symbols A ACor DC DC Measurement A AC Measurement e Continuity Test Diode Grounding E Double Insulated A Warning Refer to the Operating Manual Deficiency of Built In Battery Conforms to Standards of European Union Model UT81A B OPERATING MANUAL Reading the Screen The screen displays the menu that provides the following choices available Table 2 1 Reading the Screen Chapter 2 Using the Testing Tool Table 2 1 Reading the Screen Display Description Display Description RANGV Decrease a range Contrast The degree of contrast BASEA Increase a time base Auto Off Sleep mode time BASE V Decreas
20. ed as follows Set the rotary switch to AN Connect the test lead in series with the return circuit to be tested 4 The measured value shows on the display 5 Press MODE button to toggle between Multimeter mode and Scope mode 6 Press F1 to toggle between AC and DC current measurement C5 Figure 3 5 10A Range Measurement 25 Model UT81A B OPERATING MANUAL When measuring current the corresponding functional Note buttons After changing the measurement mode the DC REL RangA Rang autoranging will be off automatically and the AUTO F1 F2 F3 F4 will be disappeared at the bottom left of the LCD e If the value to be measured is unknown use the F1 toggle between AC or DC maximum a the F2 relative mode REL will be displayed at the right eh ace aac bottom of the LCD when it is on When the measured current is lt 5A continuous F3 select a range up measurement is allowed F4 select a range down When the measured current is between 5A 10A continuous measurement 10 seconds and interval more than 15 minutes When current measurement has been completed disconnect the connection between the testing leads and the circuit under test and remove testing leads away from the input terminals of the Meter 26 Model UT81A B OPERATING MANUAL iii Measuring R
21. erminal Meter as Figure 3 3 and proceed as follows 2 Set the rotary switch to WAN m 3 Connect the test lead in series with the return circuit to be tested 4 The measured value shows on the display ANUAS 5 Press MODE button to toggle between Multimeter mode and Scope mode 6 Press F1 to toggle between AC and DC current measurement EE SCOPE 10A mAuA COM VOHZ bee Black Red Figure 3 3 uA Range Measurement 23 mA Range Measurement To measure ACmA or currents set up the Meter as Figure 3 4 and proceed as follows SCOPE mAuA VOHZ drt 9 Figure 3 4 mA Range Measurement 24 Model UT81A B OPERATING MANUAL Insert the red test lead into the LAmA terminal and black test lead into the COM terminal Set the rotary switch to MAA Connect the test lead in series with the return circuit to be tested The measured value shows on the display Press MODE button to toggle between Multimeter mode and Scope mode Press F1 to toggle between AC and DC current measurement Model UT81A B OPERATING MANUAL 10A Range Measurement Insert the red test lead into the 10A terminal and To measure AC 10A or DC 10 currents set up black test lead into the COM terminal the Meter as Figure 3 5 and proce
22. esistance A Warning To avoid possible damages to the Meter or to the devices under test disconnect circuit power and discharge all the high voltage capacitors before measuring resistance To measure resistance set up the Meter as shown in Figure 3 6 and follow the following procedure SCOPE mAuA COM VOHZ gt HE Black Figure 3 6 Resistance Measurement 27 1 Insert the red test lead into the Q terminal and the black test lead into the COM terminal 2 Set the rotary switch to 9 3 Connect the test leads across with the object being measured 4 The measured value shows on the display When measuring resistance the corresponding functional buttons RES REL Rang A Rang V F1 F2 F3 F4 F1 toggle to diode mode F2 relative mode F3 select to a range up F4 select to a range down 28 Model UT81A B OPERATING MANUAL Note When measuring low resistance the test leads can add 0 1Q to 0 20 of error to resistance measurement To test the leads touch the probe tips together and read the resistance of the leads Take the reading obtained to subtract the resistance of the leads to get the final reading Forhigh resistance measurement gt 1MQ or low resistance measurement lt 40Q it is normal taking Several seconds to obtain a stable reading The LCD displays OL indicating open circuit without input W
23. etting is kept but will not save The setting will be lost after power off 16 Model UT81A B OPERATING MANUAL F4 Set the beeps features it can only be used under resistance diode and continuity measurement Beep ON OFF ENTER F1 F2 F3 F4 F2 turn the beep on F3 toturn the beep off F4 to confirm save and return Press functional buttons to exit the setting is kept but will not save The setting will be lost after power off Model UT81A B OPERATING MANUAL ii ACV DCV Hz ACA and DCA range Press Range to switch between DC and AC Turn the rotary switch to ACV DCV Hz ACA or DCA measurement range the Meter displays digital reading Multimeter When the frequency and amplitude of a waveform mode Press Modelto switch to waveform display is unknown press Auto scope mode as below Figure 4 When entering scope gt When the amplitude is set to auto the amplitude mode time base is auto trace the amplitude is manual indicator will be shown white text in black set you may need to re set them You could set the background When the amplitude is set to manual trigger level as well if it is needed Details of the amplitude indicator will be shown black text measurement operation of ACV DC Hz ACA or DCA in white background can be seen from B Digital Multimeter Mode gt When the time base is set t
24. hen resistance measurement has been completed disconnect the connection between the testing leads and the circuit under test and remove testing leads away from the input terminals Model UT81A B OPERATING MANUAL iv Testing Diodes A Warning To avoid harms to you please do not attempt to input voltages higher than 60V DC or 42V rms AC To avoid damages to the Meter or to the devices under test disconnect circuit power and discharge all the high voltage capacitors before testing diodes Use the diode test to check diodes transistors and other semiconductor devices The diode test sends a current through the semicondutor junction then measure the voltage drop across the junction A good silicon junction drops between 0 5V and 0 8V To test the diode out of a circuit set up the Meter as Figure 3 7 and proceed as follows SCOPE COM Black Figure 3 7 Diode Test 29 1 Insert the red test lead into the Q terminal and the black test lead into the COM terminal 2 Set the rotary switch to gt 3 For forward voltage drop readings on any semiconductor component place the red test lead on the component s anode and place the black test lead on the component s cathode The red test lead polarity is while the black test lead polarity is The measured value shows on the display When measuring diode the correspondi
25. inals with cotton bar with detergent as dirt or moisture in the terminals can affect readings Turn the Meter to OFF when it is not in use Take out the battery when it is not using for a long time Donotuse or store the Meter in a place of humidity 38 Model UT81A B OPERATING MANUAL Chapter 5 Maintaining The Test Tool high temperature explosive inflammable and strong magnetic field Model UT81A B OPERATING MANUAL B Replacing the Fuses zeg OsAa250v 10A 250V 3 Install fuses with correct type and specification 2 Remove the battery compartment case bottom 1 Remove the Figure 5 1 Fuse Replacement A Warning To avoid electrical shock or arc blast or personal injury or damage to the Meter use specified fuses ONLY in accordance with the following procedure Follow Figure 5 1 and proceed as follows to replace the Meter s fuse Turn the rotary switch to OFF and remove all connections from the terminals Remove the screw from the battery compartment and separate the battery compartment from the case bottom Remove the three screws from the case bottom and separate the case bottom from the case top Remove the
26. ity 20mV div 500V div 1 2 5 Detailed Accuracy Specifications Accuracy of reading number of least significant digits guarantee for 1 year Operating temperature 18 C 28 C Relative humidity lt 75 RH 45 Model UT81A B OPERATING MANUAL A DC Voltage Range Resolution Accuracy Overload Protection Input Impedance 400mV 100uV 4V imV Around 10MQ 40V 10mV 0 8 8 1000V DC or AC excluding waveform 400V 100mV 1000V 1V 0 1 8 B AC Voltage i Under Multimeter mode Range Resolution Accuracy Overload Protection Input Impedance 4V 1mV zd uk 1 15 1000V DC or AC Around 10MO 400V 100mV excluding waveform 750V 1V 1 2 15 Remarks Frequency Response 40Hz 400Hz Displays effective value of sine wave mean value response 46 Model UT81A B OPERATING MANUAL ii Under Scope mode The specification is same as Bi Under Multimeter mode 9 On the top right corner of the display shows the accuracy of the frequency which is around 2 When the LCD displays 1 10 period waveform the reading is valid otherwise the Meter displays C DC Current Range Resolution Accuracy Overload Protection 400uA 0 1uA 4000A 1 8 FO 5AH 250V 5 20 40mA 10 o 400mA 100A 1 2 8 4 1 F10AH 250V 5x20mm 10A 10mA 1 5 8 Continuous measurement lt 10 seconds
27. nce value shows on the display 5 The beeper comes on continuously for open conditions that is test resistance lt 10W 6 The beeper does not sound when the test resistance is gt 100W When measuring continuity buzzer the corresponding functional buttons CONTINUITY REL F1 F2 F1 toggle to resistance measurement mode F2 relative mode 32 Model UT81A B OPERATING MANUAL Note When continuity testing has been completed disconnect the connection between the testing leads and the circuit under test and remove the test leads away from the input terminals Model UT81A B OPERATING MANUAL vi Measuring Frequency Duty Cycle A Warning To avoid harms to you please do not attempt to input voltage higher than 42V rms To measure frequency and duty cycle connect the Meter as Figure 3 9 and do the following SCOPE V SER 9 B Figure 3 9 Measuring Frequency Duty Cycle Insert the red test lead into the Hz terminal and the black test lead into the COM terminal Set the rotary switch to Hz Connect the test leads across with the object being measured The measured value shows on the display Press MODE button to toggle between Multimeter mode and Scope mode Press F1 to toggle between frequency and duty cycle measurement When measuring frequency and duty cycle the corresponding fun
28. ng functional buttons DIODE REL F1 F2 F1 toggle to continuity buzzer F2 relative mode 30 Model UT81A B OPERATING MANUAL Note Connect the test leads to the proper terminals as said above to avoid error display The LCD will display OL indicating either open circuit or wrong polarity connection The unit of diode is volt V displaying the positive connection voltage drop value When diode testing has been completed disconnect the connection between the testing leads and the circuit under test and remove the test leads away from the input terminals Model UT81A B OPERATING MANUAL v Testing for Continuity A Warning To avoid harms to you please do not attempt to input voltage higher than 60V DC or 42V rms AC To avoid possible damages to the Meter or to the devices under test disconnect circuit power and discharge all the high voltage capacitors before measuring continuity To test for continuity set up the Meter as Figure 3 8 and do the following A C Lu LE CELLO mAuA IN SCOPE COM VOHZ SHE Figure 3 8 Continuity Test 31 1 Insert the red test lead into the W terminal and the black test lead into the COM terminal 2 Set the rotary switch to gt 3 Connect the test leads across with the object being tested 4 The tested circuit overload resista
29. o auto the time base indicator will be shown white text in black DC RUN background When the time base is set to manual 000 0mvi1 008kHz trace the time base indicator will be shown black text in white background gt When the time base is between 20ms 100ns it 0 28 is possible to set the auto When the time base is between 50ms 5s the auto feature will be in valid MOVE RANGA RANGY Figure 3 1 Waveform Display 17 Y axis adjustment Press Range button under scope mode the corresponding functional button Move Move Rang A Rang V F1 F2 F3 F4 F1 move up the waveform F2 move down the waveform F3 go up range F4 go down a range The auto set feature will be off when changing the measurement mode Press Time button under scope mode the corresponding functional button Base A lt gt F1 F2 F3 F4 18 Model UT81A B OPERATING MANUAL F1 increase the number of periods F2 decrease the number of periods F3 trigger point move left F4 trigger point right move The auto set feature will be off when changing the measurement mode Model UT81A B OPERATING MANUAL iii Trigger function Press Trig button under scope mode the corresponding function buttons
30. ome Auto setting Auto set the Meter according to the tested signal size Overloading Display OL Memory 10 screens and setups USB Optically isolated to ensure safety Tilt Stand Allowing viewing at a convenient position and angle 43 Feature Summary Model UT81A B OPERATING MANUAL Display 160 x 160 Monochrome Autorange Continuity When it is under multimeter mode the Meter automatically selects best range Beeper sounds for resistance readings below threshold Duty Cycle Measure signal on or off time in Battery Access Door Battery replaceable Basic Specifications Digital Multimeter Function Ranges Description DC Voltage 0 to 1000V AC Voltage 0 to 750V Basic Accuracy DC Voltage 0 8 AC Voltage 1 DC Current 0 to 10A AC Current 0 to 10A Resistance 0 to 40MQ Capacitance 0 to 100uF Frequency 0 10MHz 44 Model UT81A B OPERATING MANUAL Basic Specifications Scope Horizontal Vertical Sampling rate 40M per second Bandwidth UT81A 2MHz UT81B 8MHz Sampling rate Scale 20 pixels Channel Single Updating rate gt 5 Coupling DC Trigger types Free Run Normal Voltage resolution 8 Bits Single Shot Timebase Range 100ns div 5 sec div Input Impedance 10MQ excluding Multimeter part 1 2 5 Timebase accuracy 0 1 1pix Accuracy 5 1 pix Maximum input voltage 1000Vp p Voltage Sensitiv
31. st resistance is gt 100Q H Frequency and Duty Cycle i Under Multimeter mode Range Resolution Accuracy Overload Protection 0 10Hz 10MHz 0 001Hz 0 1 3 250V DC or AC rms 0 1 99 9 0 1 Reading for reference only Remarks Input amplitude a as follows DC electric level is zero When S1MHz 300mV lt a lt 30Vrms When gt 1MHz 600mV lt a 5Vrms 50 Model UT81A B OPERATING MANUAL Under Scope mode The specification is same as Hi Under Multimeter mode press RANGE button to toggle between frequency and duty cycle mode On the top right corner of the display shows the waveform s RMS value for reference only When the LCD displays 1 10 period waveform cycle or the peak peak difference value is greater than 1 3 div the reading is valid otherwise the Meter displays ___ Capacitance Range Resolution Accuracy Overload Protection 40nF 10pF Under REL mode 3 10 400nF 100pF 4uF 1nF 3 8 250V DC or AC rms 40uF 10nF 100uF 100nF 4 8 51 Model UT81A B OPERATING MANUAL kk END kk This operating manual is subject to change without notice 52 Model UT81A B OPERATING MANUAL Copyright 2006 Uni Trend Group Limited All rights reserved Manufacturer Uni Trend Technology Dongguan Limited Dong Fang Da Dao Bei Shan Dong Fang Industrial Development District Hu Men Town
32. suring Voltages 20 ii Measuring Currents _ _ _ _ 22 Measuring Resistance _ _ ___ __ ___ ___ ___ _____ ___ 27 iv Testing Diodes 29 v Testing for Continuity 31 vi Measuring Frequency Duty Cycle a 2 93 Model UT81A B OPERATING MANUAL Table of Contents Chapter Title Page vii Measuring Capacitance oo ooo Lol 35 4 Using Software 7 5 Maintenance The Test Tool 88 A General Service _ _ _ _ __ _ 38 B Replacing the Fuses 39 C Replacing the Battery _ _ __ __ __ __ __ _____ 40 6 Specifications 41 Safety and Compliances 41 Physical Specifications noc TA L2 42 General Specifications Digital Multimeter A AOOA 8 General Specifications Scope 0 2 0 0 43 Feature Summary T eA Basic Specifications Digital Multimeter a E 44 Basic Specifications Scope Detailed Accuracy Specifications 45 A DC Voltag
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