UNI-T UT803 Benchtop Digital Multimeter User Manual

June 9, 2024
UNI-T

UT803 Benchtop Digital Multimeter

P/N:110401104465X DATE:2018.06.26 REV.3

Model UT803: OPERATING MANUAL
TABLE OF CONTENTS
TITLE Overview Unpacking Inspection Safety Information Rules For Safe Operation International Electrical Symbols The Meter Structure Rotary Switch Functional Buttons Display Symbols Measurement Operation
A. DC or AC Voltage Measurement B. DC or AC Current Measurement C. Measuring Resistance D. Testing for Continuity E. Testing Diodes F. Capacitance Measurement G. Frequency Measurement H. Temperature Measurement I . Measuring Transistor Operation of Hold Mode The POWER Button The SELECT Button Turning on the Display Backlight The RANGE Button The MAX MIN Button AC/AC+DC Button

PAGE
3 4 5 6 8 9 10 11 12 16 16 18 20 22 24 26 28 30 32 33 33 33 34 34 35 35
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Model UT803: OPERATING MANUAL

TITLE

PAGE

POWER INPUT Switch

35

Sleep Mode

36

RS232 Button

36

General Specifications

37

Accuracy Specifications

38

A. DC Voltage

38

B. AC Voltage

39

C. DC Current

41

D. AC Current

42

E. Resistance

43

F. Continuity Test

44

G. Diode Test

44

H. Capacitance

45

I . Frequency

46

J. Temperature

47

K. Transistor

47

Maintenance

48

A. General Service

48

B. Replacing the Fuses

49

C. Replacing the Battery

51

RS232C and USB Serial Port

52

System Requirements for Installing the UT803 Interface Program

52

RS232C Serial Port

53

A. Connecting between the Meter and computer

53

B. RS232C Port Cable

54

C. Setting of RS232C Serial Ports

54

USB Serial Port

55

A. Connecting between the Meter and computer

55

B. Setting of USB Serial Ports

55

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Model UT803: OPERATING MANUAL

Overview
This Operating Manual covers information on safety and cautions. Please read the relevant information carefully and observe all the Warnings and Notes strictly.
Warning To avoid electric shock or personal injury, read the “Safety Information” and “Rules for Safety Operation” carefully before using the Meter.
Digital Bench-Type True RMS Multimeter Model UT803 (hereafter referred to as “the Meter”) has autorange and manual range options with maximum reading 5999 and 3 5/6 digits which has a unique outlook design.
In addition to all the conventional features including DC/AC voltage, current, resistance, diode, continuity test, capacitance, temperature 0C and 0F, transistor, max/min, there is a data hold, low battery display, sleep mode, RS232C and USB standard serial port for easy connection with computer to realize macro recording

and monitoring and capture of transient dynamic data, displaying change of waveform during the measurement, providing data and evidence to engineering technicians for scientific research. This is also a highly applied digital multimeter of good performance with full overload protection and display backlight function.
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Model UT803: OPERATING MANUAL
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Model UT803: OPERATING MANUAL

Safety Information
This Meter complies with the standards IEC61010: in pollution degree 2, overvoltage category (CAT. I 1000V, CAT.II 600V) and double insulation.
CAT III: Distribution level, fixed installation, with smaller transient overvoltages than CAT. IV CAT IV: Primary supply level, overhead lines, cable systems etc.
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 symbols used on the Meter and in this Operating Manual are explained on page 8.

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Model UT803: OPERATING MANUAL

Rules For Safe Operation
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:
l 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.
l 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.
l Do not apply more than the rated voltage, as marked on the Meter, between the terminals or between any terminal and grounding.
l The rotary switch should be placed in the right position and no any changeover of range shall be made during measurement is conducted to prevent damage of the Meter.
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l When the Meter working at an effective voltage over 60V in DC or 30V rms 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 If the value to be measured is unknown, use the maximum measurement position and reduce the range step by step until a satisfactory reading is obtained.
l 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.
l When using the test leads, keep your fingers behind the finger guards.
l Disconnect circuit power and discharge all highvoltage capacitors before testing resistance, continuity, diodes, current, or capacitance.
l Before measuring current, check the Meter’s fuses and turn off power to the circuit before connecting the Meter to the circuit.

Model UT803: OPERATING MANUAL

l Replace the battery as soon as the battery indicator appears. With a low battery, the Meter might
produce false readings that can lead to electric shock and personal injury. l Remove test leads, temperature probe, RS232C interface cable, USB interface cable and alligator clip from the Meter and turn the Meter power off before opening the Meter case. l When servicing the Meter, use only the same model number or identical electrical specifications replacement parts. l The internal circuit of the Meter shall not be altered at will to avoid damage of the Meter and any accident. l 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. l The Meter is suitable for indoor use.

l Turn the Meter power off when it is not in use. l Take out the battery when not using for a long time
if using battery to power on the Meter. l When using battery to power on the Meter, constantly
check the battery as it may lead when it has been using for some time, replace the battery as soon as leaking appears. A leaking battery will damage the Meter.

7

International Electrical Symbols
AC or DC Grounding Double Insulated Warning. Refer to the Operating Manual Deficiency of Built-In Battery Continuity Test Diode Capacitance Test Fuse Conforms to Standards of European Union

Model UT803: OPERATING MANUAL

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Model UT803: OPERATING MANUAL
The Meter Structure (see figure 1)

(Figure 1)

1. LCD Display 3. Input Terminals

2. Rotary Switch 4. Functional Buttons

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Model UT803: OPERATING MANUAL

Rotary Switch
Below table indicated for information about the rotary switch positions:

Rotary Switch Position
V
Hz 0F 0C hFE
A mA A

Function AC and DC voltage measurement
:Continuity test. :Diode test. :Resistance measurement. Capacitance test Hz :Frequency measurement. 0F :Temperature in Fahrenheit Temperature in celsius Transistor test AC or DC current measurement range from 0.1uA to 5999uA. AC or DC current measurement range from 0.01mA to 599.9mA. AC or DC current measurement range from 0.01A to 10.00A.

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Model UT803: OPERATING MANUAL

Functional Buttons
Below table indicated for information about the functional button operations.

Button

Operation Performed

POWER Turn the power on and off.

LIGHT Turn the display backlight on and off.

SELECT l Switches between AC and DC measurement.

l Switches between continuity and diode and resistance measurements

l Switches between frequency and Fahrenheit temperature.

HOLD Press HOLD to enter and exit the Hold mode in any mode, the Meter beeps.

RANGE Press RANGE to switch between manual and auto ranging.

RS232C Turn on or off the serial port interface without changing the original setting.

MAX MIN Starts recording of maximum and minimum values. Steps the display through high (MAX) and low (MIN).

AC AC+DC To select AC or AC+DC measurement.

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Display Symbols (see figure 2)

12 10 1 11

5.6.7 14
2 16

Auto Range Manual AC+DC Trus RMS RS232 HOLD MAX
hFE MIN
8
13 3 4
(Figure 2)

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Model UT803: OPERATING MANUAL

0C umVA
~mV Trms DC munF 0F

Mk Hz

15

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Model UT803: OPERATING MANUAL

Number 1 2 3 4 5 6 7 8 9

Symbol True RMS
HOLD
AC DC AC+DC OL ,K ,M
A, mA, µA

Meaning
Indicator for true rms value. Data hold is active. Sleep Mode feature is enabled. Indicates negative reading. Indicator for AC voltage or current. Indicator for DC voltage or current Indicator for AC+DC measurement The input value is too large for the selected range.
:Ohm. The unit of resistance. K :kilohm. 1 x 103 or 1000 ohms. M :Megaohm.1×106 or 1,000,000 ohms. 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.

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Model UT803: OPERATING MANUAL

Number 9
10 11

Symbol V, mV F, mF, µF,nF
0C, 0F Hz, kHz,
MHz

Meaning
V : Volts. The unit of voltage. mV: Millivolt.1 x 10-3 or 0.001 volts. F : Farad.The unit of capacitance. mF: Millifarad.1 x 10-3 or 0.001 farads µF : Microfarad.1×10-6 or 0.000001 farads. nF : Nanofarad.1 x 10-9 or 0.000000001 farads. Centigrade temperature Temperature in Fahrenheit Hz : Hertz. The unit of frequency in cycles/second. kHz : Kilohertz. 1 x 103 or 1,000 hertz. MHz: Megahertz. 1 x 106 or 1,000,000 hertz. Unit of transistor. Test of diode The continuity buzzer is on.

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Model UT803: OPERATING MANUAL

Number 12
13 14 15
16

Symbol AutoRange
Manual
MAX MIN RS232
hFE

Meaning Indicator of Auto or manual range
Display of maximum or minimum value. Data output is in progress. The battery is low.
Warning: To avoid false readings, which could lead to possible electric shock or personal injury, replace the battery as soon as the battery indicator appears. Transistor test is on

15

Measurement Operation
A. DC or AC Voltage Measurement (See figure 3)
Warning To avoid harms to you or damages to the Meter from electric shock, please do not attempt to measure voltages higher than 1000V although readings may be obtained.
To measure DC/AC voltage, connect the Meter as follows: 1. Insert the red test lead into the V terminal and the
black test lead into the COM terminal. If the measured value is less than 600mV, insert the red test lead into mV terminal instead and press RANGE button to select manual range 600.0mV mode, the LCD displays “MANUAL” and “mV”. 2. Set the rotary switch to V ; press SELECT button to select DC or AC measurement mode. 3. Connect the test leads across with the object being measured. The measured value shows on the display. AC measurement displays True RMS value.
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Model UT803: OPERATING MANUAL (Figure 3)

Model UT803: OPERATING MANUAL
4. Press AC/AC+DC button to measure AC+DC voltage’s true RMS.
Note l In each range, the Meter has an input impedance of
10M except 600mV range has 3000M . This loading effect can cause measurement errors in high impedance circuits. If the circuit impedance is less than or equal to 10k , the error is negligible (0.1% or less). l When DC/AC voltage measurement has been completed, disconnect the connection between the testing leads and the circuit under test, and remove the testing leads away from the input terminals of the Meter.
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B. DC or AC Current Measurement (See figure 4)
Warning Before connect the Meter in serial with the tested return circuit, close the return circuit’s current to avoid the dangerous of sparking. If the fuse burns out during measurement, the Meter may be damaged or the operator himself may be hurt. Use proper terminals, function, and range for the measurement. When the testing leads are connected to the current terminals, do not parallel them across any circuit.
To measure current, do the following: 1. Insert the red test lead into the µA mA terminal and
the black test lead into the COM terminal. 2. Set the rotary switch to an appropriate measurement
position in µA , mA or A , press SELECT button to select AC or DC measurement mode. 3. Connect the test leads in serial with the object being measured. The measured value shows on the display. AC measurement displays True RMS value. 4. Press AC/AC+DC button to measure AC+DC current’s true RMS
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Model UT803: OPERATING MANUAL (Figure 4)

Model UT803: OPERATING MANUAL
Note l If the value of current to be measured is unknown,
use the maximum measurement position, and reduce the range step by step until a satisfactory reading is obtained. l For safety sake, each measurement time of high current (>5A) should be less than 10 seconds and the interval time between 2 measurements should be greater than 15 minutes. l When current measurement has been completed, disconnect the connection between the testing leads and the circuit under test, and remove the testing leads away from the input terminals of the Meter.
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C. Measuring 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. To avoid harms to you, please do not attempt to input voltages higher than 60V DC or 30V AC.

To measure resistance, connect the Meter as follows:

1 .Insert the red test lead into the terminal and the

black test lead into the COM terminal.

2 .Set the rotary switch to

, press SELECT

button to select measurement mode.

3 .Connect the test leads across with the object being

measured. The measured value shows on the display.

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Model UT803: OPERATING MANUAL (Figure 5)

Model UT803: OPERATING MANUAL

Note l The test leads and the Meter inside wire will bring
around 0.2 to 0.5 of error to resistance measurement when measuring low resistance. To obtain accurate readings in low-resistance, shortcircuit the test lead beforehand and record the reading obtained, call this reading as X. Then use the equation: measured resistance value (Y) ­ (X) = accurate readings of resistance. l If reading with shorted test leads is not < 0.5 , check for loose test leads, incorrect function selection, or any other reasons. l When measuring high resistance (>1M ), it is normal to take several seconds to obtain a stable reading. In order to obtain stable reading, choose shorter test lead to carrying out measurement. l The LCD displays OL indicating open- circuit for the tested resistor or the resistor value is higher than the maximum range of the Meter.

l When resistance measurement has been completed, disconnect the connection between the testing leads and the circuit under test, and remove the testing leads away from the input terminals of the Meter.

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D. Testing for Continuity (See figure 6)

Warning To avoid damages to the Meter or to the devices under test, disconnect circuit power and discharge all the high-voltage capacitors before testing for continuity. To avoid harms to you, please do not attempt to input voltages higher than 60V DC or 30V AC.

To test for continuity, connect the Meter as below: 1. Insert the red test lead into the terminal and the

black test lead into the COM terminal.

2. Set the rotary switch to

and press SELECT

button to select

measurement mode.

3. Connect the test lead across with the object being

measured. The buzzer sounds if the resistance of a

circuit under test is < 10 , the circuit is in good

condition. The buzzer does not sound if the resistance

of a circuit under test is >30 , the circuit is broken.

4. The measured value shows on the display and the

unit is .

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Model UT803: OPERATING MANUAL (Figure 6)

Model UT803: OPERATING MANUAL Note l Open circuit voltage around -1.2V and range is 600 . l When continuity testing has been completed,
disconnect the connection between the testing leads and the circuit under test, and remove the testing leads away from the input terminals of the Meter.
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E. Testing Diodes (See figure 7)
Warning To avoid possible damage to the Meter and to the device under test, disconnect circuit power and discharge all high-voltage capacitors before testing diodes. To avoid harms to you, please do not attempt to input voltages higher than 60V DC or 30V AC. Use the diode test to check diodes, transistors, and other semiconductor devices. The diode test sends a current through the semiconductor junction, and then measures the voltage drop across the junction. A good silicon junction drops between 0.5V and 0.8V.
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Model UT803: OPERATING MANUAL (Figure 7)

Model UT803: OPERATING MANUAL

To test a diode out of a circuit, connect the Meter as follows:

1. Insert the red test lead into terminal and the black

test lead into the COM terminal.

2. Set the rotary switch to

and press SELECT

button to select

measurement mode.

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 measured

value shows on the display.

Note
l Connect the test leads to the proper terminals as said above to avoid error display. The LCD will display OL indicating diode being tested is open or polarity is reversed. The unit of diode is Volt (V), displaying the forward voltage drop readings.
l Open circuit voltage is around 2.7V.

l When diode testing has been completed, disconnect the connection between the testing leads and the circuit under test, and remove the testing leads away from the input terminals of the Meter.

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F. Capacitance Measurement (See figure 8)
Warning To avoid damage to the Meter or to the equipment under test, disconnect circuit power and discharge all high-voltage capacitors before measuring capacitance. Use the DC Voltage function to confirm that the capacitor is discharged. To measure capacitance, connect the Meter as follows:

  1. Insert the red test lead into the Hz mV terminal and
    the black test lead into the COM terminal. 2. Set the rotary switch to . 3. Connect the test leads across with the object being
    measured. The measured value shows on the display.
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Model UT803: OPERATING MANUAL (Figure 8)

Model UT803: OPERATING MANUAL

Note
l The Meter displays a fixed value which is the distributed capacitor’s value of the inside Meter. To ensure accuracy, it is necessary to subtract this value from the measured value when measuring small capacitor.
l Multi-purpose socket can be used instead of testing leads. Insert the capacitor being tested into the corresponding input terminal of the multi- purpose socket. When measuring small capacitor value, more accurate value can be obtained using multipurpose socket.
l It is normal to take a longer time when testing a capacitor value higher than 600µF.
l The LCD displays OL indicating the tested capacitor is shorted or it exceeds the maximum range.

l When capacitance measurement has been completed, disconnect the connection between the testing leads and the circuit under test and remove the testing leads away from the input terminals of the Meter.

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G. Frequency Measurement (see figure 9) Warning
To avoid harms to you, please do not attempt to input tested frequency’s voltages higher than 30V rms. To measure frequency, connect the Meter as follows: 1. Insert the red test lead into the Hz terminal and the
black test lead into the COM terminal. 2. Set the rotary switch to Hz0F and press SELECT
button to select Hz measurement mode. 3. Connect the test leads across with the object being
measured. The measured value shows on the display.
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Model UT803: OPERATING MANUAL (Figure 9)

Model UT803: OPERATING MANUAL

Note

l When making frequency measurement, it must comply

with the following scope (a) requirement:

When 10Hz ~ 1Mz

:150mV a 30V rms

When > 1Mz~ 10MHz

:300mV a 30V rms

When > 10Mz~ 50MHz :600mV a 30V rms

When > 50Mz

:Unspecified

l When frequency measurement has been completed,

disconnect the connection between the testing leads

and the circuit under test, and remove the testing

leads away from the input terminals of the Meter.

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H. Temperature Measurement (see figure 10)
Warning To avoid harms to you, please do not attempt to input voltages higher than 60V DC or 30V AC. To measure temperature, connect the Meter as follows:

  1. Set the rotary switch to 0C to measure degree celsius
    temperature or Hz0F and press SELECT button to select 0F measurement mode to measure Fahrenheit temperature. 2. Insert the multi-purpose socket into the corresponding Hz and COM terminal. 3. Insert the temperature probe to the corresponding input terminal of the multi-purpose socket. 4. Place the temperature probe to the object being measured. The measured value shows on the display after few seconds.
    30

Model UT803: OPERATING MANUAL (Figure 10)

Model UT803: OPERATING MANUAL

Note l The testing environment must between 180C to 280C
to ensure accuracy especially when measuring low temperature. l Different reading may be obtained when testing room environment under short or open circuit situation, then short-circuited reading shall be considered as the correct reading. l The included point contact temperature probe can only be used under 2300C. For any measurement higher than that, the rod type temperature probe must be used instead.

l When temperature measurement has been completed, disconnect the connection between the temperature probe, multi-purpose socket and the circuit under test, and remove the temperature probe away from the input terminals of the multi-purpose socket, and remove the multi-purpose socket away from the input terminals of the Meter.

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I. Measuring Transistor (see figure 11)
Warning To avoid harms to you, please do not attempt to input voltages higher than 60V DC or 30V AC.
To measure transistor, connect the Meter as follows: 1. Insert the multi- purpose socket into the µAmA and
Hz input terminal. 2. Set the rotary switch to hFE. 3. Insert the NPN or PNP type transistor to be tested
into the corresponding input terminals of the multipurpose socket. 4. The measured nearest transistor value shows on the display.
Note l When transistor measeurement has been completed,
remove the tested transistor from the multi-purpose socket and remove the multi-purpose scoket from the input terminal
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Model UT803: OPERATING MANUAL

PNP

NPN
(Figure 11)

Model UT803: OPERATING MANUAL

Operation of Hold Mode
Warning To avoid possibility of electric shock, do not use Hold mode to determine if circuits are without power. The Hold mode will not capture unstable or noisy readings.
The Hold mode is applicable to all measurement functions.
l Press HOLD to enter Hold mode. l Press HOLD again to exit Hold mode and the Meter
displays the present measurement value. l In Hold mode, is displayed.

The SELECT Button
It uses for selecting the required measurement function when there is more than one function at one position of the rotary switch.

The POWER Button
This is a self-lock switch uses to turn on or off the power of the Meter. It is located at the tail of the Meter. “I” means power up the Meter while “O” means power off the Meter.

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Model UT803: OPERATING MANUAL

Turning on the Display Backlight
Warning In order to avoid the hazard arising from mistaken readings in insufficient light or poor vision, please use Display Backlight function.
l Press LIGHT button to turn the Display Backlight on. l Press LIGHT button again to turn the Display Backlight
off, otherwise it will stay on continuously. l When using the AC power to turn the Meter on, the
Display Backlight always stays on.

The RANGE Button
l Press RANGE to enter the manual ranging mode; the Meter beeps.
l Press and hold RANGE for over 1 second to return to autoranging; the Meter beeps.

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Model UT803: OPERATING MANUAL

The MAX MIN Button
MAX MIN recording mode captures and stores the maximum and minimum input value detected.
To use the MAX MIN mode as follows: l Press MAX MIN to display the highest reading
( MAX is shown on display). l Press MAX MIN again to display the lowest reading
( MIN is shown on display). Press and hold MAX MIN for over 1 second to exit the MAX MIN mode.

POWER INPUT Switch
It is used to select AC 110V/50Hz or DC 6pcs of 1.5V battery (R14) to power on the Meter. It is located at the tail of the Meter.

AC/AC+DC Button
It is used to select measuring AC or AC+DC when measuring AC. Press it only at the AC voltage or current measuring mode which is at the rotary switch position V , mV ,µA , mA or A . “+DC ” will be displayed when it is pressed under DC measurement mode.
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Model UT803: OPERATING MANUAL

Sleep Mode
When the Meter display symbol, it automatically turns off if you do not turn the rotary switch or press any button for around 10 minutes to preserve battery. The last measurement value will be kept.
The Meter can be activated by pressing the POWER button off and then on or pressing the HOLD button, it will display the last measurement value before it entered sleep mode and under the HOLD mode. Turning the rotary switch can also activate the Meter. However, it will start from the switch selected function and it will not display the last measurement value before it entered sleep mode.
To disable the Sleep Mode function, press MAX MIN, RANGE, or RS232 button while turning on the Meter, the symbol disappears.

RS232 Button
Press RS232 button to enter or exit data output mode. In RS232C serial port data output mode, the Hold and Max Min mode cannot output to the computer, the computer will only display the present measuring value. In RS232C serial port data output mode, Sleep Mode function will be disabled, symbol disappears. +DC, hFE and cannot output to the computer.

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Model UT803: OPERATING MANUAL

General Specifications

l Maximum Voltage between any Terminals and Grounding:

Refer to different range input protection voltage.

l Fused Protection for HzmV Input Terminal: 200mA, 250V, fast type, 5x20mm (only apply on

hFE functions)

l Fused Protection for µAmA Input Terminal: 500mA, 125V, fast type, 5x20mm.

l Fused Protection for 10A Input Terminal:

10A, 250V, fast type, 5x20mm.

l Fused Protection for AC110V Terminal:

500mA, 125V, fast type, 5x20mm.

At AC110V power: without fuse protection.

l Maximum Display : Digital: 5999

l Measurement Speed: Updates 2-3 times/second.

l Range

: Manual or auto ranging.

l Polarity Display : Auto

l Overloading Display : OL

l Temperature: Operating: 00C to +400C (320F to +1040F). Storage : -100C to +500C (140F to +1220F).

l Relative Humidity: 75% @ 00C – 300C below; 50% @ 30 – 400C.
l Altitude: Operating: 2000 m. Storage : 10000 m.
l Below 1V/m electrostatic discharge: Accuracy = specified accuracy + 5% of the range. Over 1V/m electrostatic discharge:Without specified accuracy.
l Power: AC110V/50Hz or 6 pieces of 1.5V battery (R14).
l Battery Deficiency: Display
l Dimensions (HxWxL): 105 x 240 x 310 mm.
l Weight: Approximate 2kg (accessories excluded).
l Safety/Compliances: IEC61010 CAT. I 1000V, CAT. II 600V overvoltage and double insulation standard.
l Certifications: , UL pending.
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Accuracy Specifications
Accuracy: (a% reading + b digits),guarantee for 1 year. Operating temperature: 230C 50C. Relative humidity: not more than 75% RH. Temperature coefficient: 0.1 x (specified accuracy)/10C.

A. DC Voltage

Range 600mV
6V 60V 600V 1000V

Resolution 0.1mV 0.001V 0.01V 0.1V 1V

Remarks: l Input Impedance:
At 600mV range : Around > 3000M . At all other ranges: Around 10M .

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Model UT803: OPERATING MANUAL

Accuracy (0.6%+2)
(0.3%+2)
(0.5%+3)

Overload Protection 1000V

Model UT803: OPERATING MANUAL

B. AC Voltage Range 600mV
6V

Resolution 0.1mV
0.001V

60V
600V 1000V

0.01V
0.1V 1V

Accuracy 40Hz-50kHz: (0.6%+5) >50kHZ-100kHz: (1%+5) 40Hz-1kHz: (0.6%+5) >1kHz- 10kHz: (1.0%+5) >10kHz-100kHz: (3%+5) 40Hz-1kHz: (0.6%+5) >1kHz-10kHz: (1.5%+5) >10kHz-20kHz: (3%+5) >20kHz-100kHz: (8%+5) 40Hz-1kHz: (0.6%+5) >1kHz- 10kHz: (3.5%+5) 40Hz-1kHz: (1.2%+3) >1kHz-3kHz: (3%+3)

Overload Protection 1000V

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Model UT803: OPERATING MANUAL
Remarks: l Input Impedance:
At 600mV range : Around > 3000M At all other ranges: Around 10M l Displays:
True RMS (applicable to the range of 10%~95%) At 1000V range: AC peak factor 1.5. All other ranges: AC peak factor 3.0. Input short circuit has around less than 30 remaining digits, it will not affect accuracy. AC+DC measurement accuracy = range’s accuracy + 1%
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Model UT803: OPERATING MANUAL

C. DC Current

Range 600µA 6000µA 60mA 600mA
10A

Resolution 0.1µA 1µA 0.01mA 0.1mA
10mA

Accuracy (0.5%+3) (0.8%+3) (1.2%+3)

Overload Protection
Fuse 500mA, 125V, fast type, 5x20mm.
Fuse 10A, 250V, fast type, 5x20mm.

Remarks: l At 5A range: Continuous measurement is allowed. l At >5A range: For continuous measurement 10 seconds and interval not less than 15 minutes.

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Model UT803: OPERATING MANUAL

D. AC Current

Range 600µA 6000µA 60mA 600mA
10A

Resolution 0.1µA 1µA 0.01mA 0.1mA
10mA

Accuracy
40Hz~10kHz: (1.0%+5) >10kHz~15kHz: (2%+5) 40Hz~10kHz: (1%+5) >10kHz~15kHz: (3%+5) 40Hz~5kHz: (2.0%+6)

Overload Protection Fuse 500mA, 125V, fast
type, 5x20mm.
Fuse 10A,250V, fast type, 5x20mm.

Remarks:
l At 5A range: Continuous measurement is allowed. l At >5A range : For continuous measurement 10 seconds and interval not less than 15 minutes. l Displays:
True RMS (applicable to the range of 10%~95%) AC peak factor 3.0. Input short circuit has around less than 30 remaining digits, it will not affect accuracy.
AC+DC measurement accuracy = range’s accuracy + 1%

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Model UT803: OPERATING MANUAL

E. Resistance
Range
600
6k 60k 600k 6M 60M

Resolution
0.1
0.001k 0.01k 0.1k 0.001M 0.01M

Accuracy (0.8%+3) + test lead short circuit resistance value
(0.5%+2)
(0.8%+2) (1.2%+3)

Overload Protection 250V rms

43

Model UT803: OPERATING MANUAL

F. Continuity Test Range

Resolution 1

Overload Protection

Remarks

250V rms

l Open circuit voltage approximate -1.2V. l When circuit disconnected with resistance value

30 , buzzer does not beep.

l When circuit is in good connection with resistance value 10 buzzer beeps continuously.

G. Diode Testst Range

Resolution 10mV

Overload Protection

Remarks

250V rms

l Open circuit voltage approximate 2.7V. l Working current approximate 1mA.

44

Model UT803: OPERATING MANUAL

H. Capacitance

Range 6nF 60nF 600nF 6µF 60µF 600µF 6mF

Resolution 0.001nF 0.01nF 0.1nF 0.001µF 0.01µF 0.1µF 0.001mF

Accuracy (2.5%+5)
(2%+5) (3%+4) (5%+4)

Overload Protection 250V rms

Remarks: l At 6nF, 60nF and 600nF Range: reading must subtract the test lead open circuit capacitance value.

45

I. Frequency

Range 6kHz 60kHz 600kHz 6MHz 60MHz

Resolution 0.001kHz 0.01kHz
0.1kHz 0.001MHz 0.01MHz

Remarks:

l Input scope (a): (DC electric level is zero)

When 10Hz ~ 1MHz : 150mV a 30V rms

When > 1MHz ~ 10MHz : 300mV a 30V rms

When > 10MHz ~ 50MHz : 600mV a 30V rms

When > 50MHz

: Unspecified

Model UT803: OPERATING MANUAL

Accuracy (0.1%+3)

Overload Protection 250V rms

46

Model UT803: OPERATING MANUAL

J. Temperature

Range 0C
0F

Resolution 10C
10F

Accuracy

-400C~00C

(8%+5)

00C~4000C

(1%+3)

4000C~10000C

(1.5%+3)

-400C~320C

(8%+5)

320F~7520F

(1.5%+5)

7520F~18320F

(2.5%+5)

Overload Protection 250V rms

Remarks: l The included point contact temperature probe can only be used to measure under 2300C temperature. For any
measurement higher than that, the rod type temperature probe must be used instead.

K. Transistor Range hFE

Resolution 1

Overload Protection l Fuse 200mA, 250V, fast type, 5x20mm. l Fuse 500mA, 125V, fast type, 5x20mm

Remarks Vce 2.2V bo 10µA
1000 MAX
47

Model UT803: OPERATING MANUAL

Maintenance
This section provides basic maintenance information including battery and fuse replacement instruction.
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. To avoid electrical shock or damage to the Meter, do you get water 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 off the power of the Meter when it is not in use. l Take out the battery when it is using for a long time. l Do not use or store the Meter in a place of humidity,
high temperature, explosive, inflammable and strong magnetic field.

48

Model UT803: OPERATING MANUAL
B. Replacing the Fuses (see figure 12)
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.
To replace the Meter’s fuse: 1. Press the POWER to turn the Meter off, disconnect
the power cord and remove all connections from the terminals. 2. Fuse 1: Remove the screws from the power socket at the rear of the Meter. Remove the fuse by gently prying one end loose, then take out the fuse from its bracket. Then install the replacement fuse. Fuse 2 and 3: Use a coin to open the accessories compartment at the top of the front cover, then you will see a fuse compartment. Open the fuse compartment to replace fuse 2 and 3. Remove the fuse by gently prying one end loose, then take out the fuse from its bracket. Then install the replacement fuse.

(Figure 12) 49

Fuse 4:It is located at the PCB. Remove the fuse by gently prying one end loose, then take out the fuse from its bracket. Then install the replacement fuse 3. 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: 500mA, 125V, fast type, 5x20mm (AC110V) Fuse 2: 10A, 250V, fast type, 5×20 mm (A) Fuse 3: 500mA, 125V, fast type, 5×20 mm (µA, mA) Fuse 4: 200mA, 250V, fast type, 5×20 mm (hFE)
Replacement of the fuses is seldom required. Burning of a fuse always results from improper operation.

Model UT803: OPERATING MANUAL

50

Model UT803: OPERATING MANUAL
C. Replacing the Battery (see figure 13)
Warning To avoid false readings, which could lead to possible electric shock or personal injury, replace the battery as soon as the battery indicator ” ” appears when using battery to power on the Meter.
To replace the battery: 1. Press the POWER to turn the Meter off and remove
all connections from the terminals. 2. Use a coin to open the accessories compartment at
the top of the front case. 3. Use a coin to open the battery compartment inside
the accessories compartment located at the top of he front case. 4. Remove all the batteries from the battery compartment. 5. Replace the battery with new 6pcs of 1.5V battery (R14). 6..Rejoin the battery compartment and also the accessories compartment located at the top of the front case.

(Figure 13) 51

RS232C and USB Serial Port
System Requirements for Installing the UT803 Interface Program To use UT803 Interface Program, you need the following hardware and software: l An IBM PC or equivalent computer with 80486 or
higher processor and 600 x 800 pixel or better monitor. l Microsoft Windows 95 or above. l At least 8MB of RAM. l At least 8MB free space in hard drive. l Can access to a local or a network CD-ROM. l A free serial port. l A mouse or other pointing device supported by
Windows.
52

Model UT803: OPERATING MANUAL

Model UT803: OPERATING MANUAL

RS232C Serial Port
A. Connecting between the Meter and computer (see figure 14)

UT803 Back Faceplate

To COMPUTER

(Figure 14) 53

B. RS232C Port Cable

The Meter D-sub
9 Pin Male 1 (DCD) 2 (RXD) 3 (TXD) 4 (DTR) 5 (SG) 6 (DSR) 7 (RTS) 8 (CTS) 9 (RI)

Computer

D-sub

D-sub

9 Pin Female 25 Pin Female

1 (DCD)

8 (DCD)

3 (TXD)

2 (TXD)

2 (RXD)

3 (RXD)

4 (DTR)

20 (DTR)

5 (SG)

7 (SG)

6 (DSR)

6 (DSR)

7 (RTS)

4 (RTS)

8 (CTS)

5 (CTS)

9 (RI)

22 (RI)

Model UT803: OPERATING MANUAL

C. Setting of RS232C Serial Ports

Default of RS232C serial port for communication is set as:

Baud Rate

19200

Start bit

1

Stop bit

1

Data bits

7

Parity Odd

54

Model UT803: OPERATING MANUAL
USB Serial Port
A. Connecting between the Meter and computer (see figure 15)
B. Setting of USB Serial Ports Install the USB serial port driver according to the Installation Guide & Computer Interface Software before connecting the Meter and computer.
Check for the USB Serial port shown at the Control Panel => System => Device Manager. Make sure connect the Meter and the computer with the same port.
Please refer to the included “Installation Guide & Computer Interface Software” for installing and operating instructions of the UT803 Interface Program..
The Meter is to be supplied from an identical USB port complying with the requirement of Limit Power Source.
END

UT803 Back Faceplate To COMPUTER USB INTERFACE CABLE
(Figure 15)
55

Model UT803: OPERATING MANUAL
56

1 (210×142)±1mm

2 128g,60g56

3

4 ,….

5

6 /

7

110401103706

REV.3

DWH
CHK
APPRO.

2018.06.25

MODEL
:UT803

Part NO. :110401104465X

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