UNI-T UT90A Operating Manual Download Page 28

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Accuracy Specification(1)

Accuracy: (a% r b digits),guarantee for 1 year.
Operating temperature:18

C~28

Relative humidity:<75%RH.
Temperature coefficient: 0.1 x (specified accuracy) / 1

Remark: Input impedance:

10M

Ω

A. DC Voltage

200mV

20V

200V

1000V

0.1mV

1mV

10mV

100mV

Range

Resolution

(0.5%+2)

Overload
Protection

Accuracy

230VAC

(0.8%+3)

1000V DC

or 750V AC

rms.

continuous.

B. AC Voltage

20V

200V
750V

1mV

10mV

100mV

Range

Resolution

(0.8%+5)

Overload
Protection

Accuracy

(1.0%+5)

1000V DC

or 750V AC

rms.

continuous.

Remarks:

Input impedance:

10M

Ω

Frequency response:

40Hz~400Hz.

Display effective value of sine wave (mean value

response).

Model UT90A: OPERATING MANUAL

Summary of Contents for UT90A

Page 1: ...ltage Measurement C DC Current Measurement D AC Current Measurement E Resistance Measurement F Testing Diodes Continuity G Battery Test General Specifications Accuracy Specifications A DC Voltage B AC Voltage C DC Current D AC Current E Resistance F Diodes Continuity Test Maintenance A General Service B Replacing the Fuses C Replacing the Battery 3 4 5 6 8 9 10 32 11 12 14 14 16 17 19 20 22 24 26 ...

Page 2: ...Model UT90A OPERATING MANUAL 2 ...

Page 3: ...re using the Meter The Model UT90A hereafter referred to as the Meter is a 1999 counts 3 1 2 digits multimeter with stabilized functions safe design and reliable performance In addition to the conventional measuring function such as DC AC voltage DC AC current resistance diode and continuity it is also a highly applied digital electrical tester of good performance with battery test large LCD full ...

Page 4: ...arefully to see any missing or damaged part In the event you find any missing or damage please contact your dealer immediately Holster Model UT90A OPERATING MANUAL 4 Item 1 2 3 4 Description English Operating Manual Test Lead 9V Battery NEDA 1604 6F22 or 006P Qty 1 piece 1 pair 1 piece 1 piece ...

Page 5: ... smaller transient overvoltages 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 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 on International electrical sy...

Page 6: ...behind the finger guards l Do not apply more than the rated voltage as marked on the Meter between the terminals or between any terminal and grounding l When the Meter working at an effective voltage over 60V in DC or 30V in AC special care should be taken for there is danger of electric shock l Use the proper terminals function and range for your measurements l The rotary switch should be placed ...

Page 7: ...prevent the surface of the Meter from corrosion damage and accident l Turn off the Meter when it is not in use and take out the battery when not using for a long time l Constantly check the battery 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 l Do not use or store the Meter in an environment of high tempe...

Page 8: ...lternating Current DC Direct Current AC or DC Grounding Double Insulated Deficiency of Built In Battery Continuity Test Diode Fuse Warning Refer to the Operating Manual Conforms to Standards of European Union Model UT90A OPERATING MANUAL 8 ...

Page 9: ...The Meter Structure see figure 1 9 figure 1 1 LCD Display 2 Hold Button 3 Rotary Switch 4 Input Terminals 5 Power Button Model UT90A OPERATING MANUAL ...

Page 10: ...10 AC Current Measurement Range from 0 1µA to 10A Model UT90A OPERATING MANUAL µ ...

Page 11: ...ion about the functional button operations AC voltage measurement Turn the power on and off l Press HOLD once to enter hold mode l Press HOLD again to exit hold mode and the present value is shown l In Hold mode is displayed HOLD Model UT90A OPERATING MANUAL ...

Page 12: ...e battery as soon as the battery indicator appears 2 4 Indicates negative reading 5 Test of diode 6 The continuity buzzer is on 7 Date hold is active 8 High voltage indicator Indicator for AC voltage or current The displayed value is the mean value 3 AC Connect Terminal Indicator of connecting test leads into different input terminals AC µAmAA Ω mVV k M Ω Ω Model UT90A OPERATING MANUAL ...

Page 13: ...ms MΩ Megaohm 1 x 106 or 1 000 000 ohms µA mA A A Amperes amps The unit of current mA Milliamp 1 x 10 3 or 0 001 amperes µA Microamp 1x 10 6 or 0 000001 amperes V Volts The unit of voltage mV Millivolt 1 x 10 3 or 0 001 volts No Symbol Meaning 9 Ω kΩ MΩ mV V 13 Model UT90A OPERATING MANUAL ...

Page 14: ...000V To measure DC voltage connect the Meter as follows 1 Insert the red test lead into the VΩ terminal and the black test lead into the COM terminal 2 Set the rotary switch to an appropriate measurement position in V 3 Connect the test leads across with the object being measured The measured value shows on the display Note l If the value of voltage to be measured is unknown use the maximum measur...

Page 15: ... each range the Meter has an input impedance of approx 10MΩ This loading effect can cause measurement errors in high impedance circuits If the circuit impedance is less than or equal to 10kΩ the error is negligible 0 1 or less l When DC voltage measurement has been completed disconnect the connection between the testing leads and the circuit under test Model UT90A OPERATING MANUAL ...

Page 16: ...the Meter as follows 1 Insert the red test lead into the VΩ terminal and the black test lead into the COM terminal 2 Set the rotary switch to an appropriate measurement position in V range 3 Connect the test leads across with the object being measured The measured value shows on the display which is effective value of sine wave mean value response Note l If the value of voltage to be measured is u...

Page 17: ...C voltage measurement has been completed disconnect the connection between the testing leads and the circuit under test C DC Current Measurement see figure 4 Warning Never attempt an in circuit current measurement where the open circuit voltage between terminals and ground is greater than 60V DC or 30V rms If the fuse burns out during measurement the Meter may be damaged or the operator himself ma...

Page 18: ...t path to be tested Connect the red test lead to the more positive side of the break and the black test lead to the more negative side of the break 5 Turn on power to the circuit The measured value shows on the display Measurement Operation 5 Note l If the value of current to be measured is unknown use the maximum measurement position 10A and 10A terminal and reduce the range step by step until a ...

Page 19: ...he testing leads are connected to the current terminals do not parallel them across any circuit The measurement ranges of AC current are 200 0µA 2 000mA 20 00mA 200 0mA and 10 00A To measure current do the following 1 Turn off power to the circuit Discharge all high voltage capacitors 2 Insert the red test lead into the µAmA or 10A terminal and the black test lead into the COM terminal 3 Set the r...

Page 20: ...g Resistance see figure 5 Warning To avoid damages to the Meter or to the devices under test disconnect circuit power and discharge all the high voltage capacitors before measuring resistance red black figure 5 Model UT90A OPERATING MANUAL ...

Page 21: ...ort circuit the input terminals beforehand and record the reading obtained called this reading as X X is the additional resistance from the test lead Then use the equation measured resistance value Y X precision readings of resistance l When the resistance reading 0 5 in the short circuit condition please check for loose test leads or other reasons l For high resistance 1M it is normal taking seve...

Page 22: ...nction then measures the voltage drop across the junction A good silicon junction drops between 0 5V and 0 8V To test a diode out of a circuit connect the Meter as follows 1 Insert the red test lead into the VΩ terminal and the black test lead into the COM terminal 2 Set the rotary switch to 3 For forward voltage drop readings on any semiconductor component place the red test lead on the component...

Page 23: ...as said above to avoid error display l The open circuit voltage is around 3V when testing diode l The LCD will display 1 indicating open circuit for wrong connection l The unit of diode is Volt V displaying the positive connection voltage drop value l When diode testing has been completed disconnect the connection between the testing leads and the circuit under test Measurement Operation 10 Testin...

Page 24: ...istance value is 100Ω The circuit is disconnected The buzzer sounds continuously when the resistance value is 10Ω The circuit is in good condition Note l The LCD displays 1 indicating the circuit being tested is open l Open circuit voltage is approx 3V l When continuity testing has been completed disconnect the connection between the testing leads and the circuit under test G Battery Test see figu...

Page 25: ...d into the COM terminal 2 Set the rotary switch to an appropriate measurement position in range 3 Parallel connect the red test lead on the anode of the battery being tested and place the black test lead on the cathode 4 The measured value shows on the display Note l The range of 1 5V only fit for the measure of 1 5V Battery Inside load resistance is 38Ω l The range of 9V only fit for the measure ...

Page 26: ...F Storage 10 o C 50 o C 14 o F 122 o F l Relative Humidity 75 0 o Cto below 30 o C 50 30 o Cto 40 o C l Altitude Operating 2000m Storage 10000m l Battery Type One piece of 9V NEDA 1604 or 6F22 or 006P l Electro Magnetic When it is under 1V m frequency total accuracy assigned accuracy 5 of the range When it is over 1V m frequency there is no assigned accuracy l Battery Deficiency Display l Negative...

Page 27: ...27 General Specifications 2 l Safety Compliances IEC61010 CAT II 1000V CAT III 600V overvoltage and double insulation standard l Certification Model UT90A OPERATING MANUAL ...

Page 28: ...00mV 2V 20V 200V 1000V 0 1mV 1mV 10mV 100mV 1V Range Resolution 0 5 2 Overload Protection Accuracy 230VAC 0 8 3 1000V DC or 750VAC rms continuous B AC Voltage 2V 20V 200V 750V 1mV 10mV 100mV 1V Range Resolution 0 8 5 Overload Protection Accuracy 1 0 5 1000V DC or 750VAC rms continuous Remarks l Input impedance 10MΩ l Frequency response 40Hz 400Hz l Display effective value of sine wave mean value r...

Page 29: ...t greater than 15 minutes l Displays effective value of sine wave mean value response C DC Current 200µA 2mA 20mA 200mA 10A 0 1µA 1µA 10µA 0 1mA 10mA Range Resolution 0 8 2 Overload Protection Accuracy 1 2 5 Fuse 315mA 250V fast type 5x20mm Fuse 10A 250V fast type 5x20mm D AC Current 200µA 2mA 20mA 200mA 10A 0 1µA 1µA 10µA 0 1mA 10mA Range Resolution 1 0 5 Overload Protection Accuracy 2 0 5 Fuse 3...

Page 30: ...V rms F Diodes Continuity Test 1mV 1Ω Range Resolution Overload Protection 230V rms Remarks l At Range Open circuit voltage approximate 3V l At Range Open circuit voltage approximate 3V The buzzer does not sound when the resistance value is 100Ω The circuit is disconnected The buzzer sounds continuously when the resistance value is 10Ω The circuit is in good condition Model UT90A OPERATING MANUAL ...

Page 31: ...ter inside the case A General Service l Periodically wipe the case with a damp cloth and mild detergent Do not use abrasives or solvents l To clean the terminals with cotton bar with detergent as dirt or moisture in the terminals can affect readings l Turn the Meter off when it is not in use and take out the battery when not using for a long time l Do not store the Meter in a place of humidity hig...

Page 32: ...with the identical type and specification as follows and make sure the fuse is fixed firmly in the bracket Fuse 1 10A 250V fast type 5x20 mm Fuse 2 315mA 250V fast type 5x20 mm 6 Rejoin the case bottom and case top and reinstall the 3 screws and holster Replacement of the fuses is seldom required Burning of a fuse always results from improper operation C Replacing the Battery see figure 9 Warning ...

Page 33: ...ase bottom 4 Remove the battery from the battery connector 5 Replace with a new 9V battery NEDA1604 6F22 or 006P 6 Rejoin the case bottom and case top and reinstall the 3 screws and the holster END This operating manual is subject to change without notice Model UT90A OPERATING MANUAL ...

Page 34: ...34 Model UT90A OPERATING MANUAL ...

Page 35: ...35 Model UT90A OPERATING MANUAL ...

Page 36: ...a Dao Bei Shan Dong Fang Industrial Development District Hu Men Town Dong Guan City Guang Dong Province China Headquarters Uni Trend International Limited Address 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 Model UT90A OPERATING MANUAL ...

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