UNI-T UT50A, UT50B, UT50C Operating Manual

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Model UT50A/B/C: OPERATING MANUAL

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Table of Contents

Title

Overview
Unpacking Inspection
Safety Information
Rules For Safe Operation
International Electrical Symbols
The multimeter Structure
Functional Buttons

Display Symbols
Measurement Operation

A. DC Voltage Measurement
B. AC Voltage Measurement
C. DC Current Measurement

D. AC Current Measurement

E. Measuring Resistance
F. The Model UT50C:

Frequency Measurement
G. The Model UT50B/UT50C:

Temperature Measurement

H. Capacitance Measurement
I. Measuring Diodes & Continuity

General Specifications

Testing for Continuity
Sleep Mode
Turning on the Auto Display Backlight

Accuracy Specifications

A. DC Voltage
B. AC Voltage
C. DC Current
D. AC Current

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I. Diodes and Continuity Test

30
30

C. Replacing the Fuses

31
32

32
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Model UT50A/B/C: OPERATING MANUAL

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Title

E. Resistance Test
F. The Model UT50C: Frequency
G. The Model UT50B/UT50C:

Temperature
H. Capacitance

Maintenance

A. General Service
B. Replacing the Battery

Overview

Warning
To avoid electric shock or personal injury, read the
"Safety Information" and "Rules for Safe Operation"
carefully before using the Meter.

Digital Multimeters Model UT50A, UT50B and UT50C
(hereafter referred to as “the Meter”) are 3 1/2 digits with
steady operations, fashionable structure and highly
reliable hand-held measuring instrument. The Meter uses
large scale of integrated circuit with double integrated
A/D converter as its core and has full range overload
protection. The Meter not only can measure AC/DC
Voltage, AC/DC Current, Resistance, Capacitance,
Temperature, Frequency , Diodes and Continuity, but also
has Data Hold, Full Icon Display and Sleep Mode features.

The Meter adopted advanced “co-injection” technique in
order to provide sufficient insulation and anti-shaking.
In addition, the Automatic Display Backlight feature
enables user to work in a dim condition.

Model UT50A/B/C: OPERATING MANUAL

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Unpacking Inspection

Open the package case and take out the Meter. Check
the following items carefully to see any missing or
damaged part:

In the event you find any missing or damage, please
contact your dealer immediately.

Model UT50A/B/C: OPERATING MANUAL

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Item

1
2

3
4

Description

English Operating Manual
Test Lead
Test Clip

Point Contact Temperature Probe
(UT50B/UT50C only)

Qty

1 piece

1 pair
1 pair

1 piece

Safety Information

This Meter complies with the standards IEC61010: in
pollution degree 2, overvoltage category (CA T. II 1000V,
CAT. III 600V) and double insulation.

CA T. II: Local level, appliance, PORTABLE EQUIPMENT
etc., with smaller transient voltage overvoltages than
CAT. III
CA T. III: Distribution level, fixed installation, with 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 symbols used on the Meter and
in this Operating Manual are explained on page 8.

Model UT50A/B/C: OPERATING MANUAL

5

Rules For Safe Operation (1)

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.
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 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.

Model UT50A/B/C: OPERATING MANUAL

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Rules For Safe Operation (2)

l Disconnect circuit power and discharge all high­ voltage capacitors before testing resistance,
continuity, diodes, capacitance or current.
l Before measuring current, check the Meter’s
fuses and turn off power to the circuit before
connecting the Meter to the circuit.
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, test clips and temperature
probe 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

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.

Model UT50A/B/C: OPERATING MANUAL

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International Electrical Symbols

AC (Alternating Current).
DC (Direct Current).
AC or DC.
Grounding.
Double Insulated.
Deficiency of Built-In Battery.
Continuity Test.
Diode.
Capacitance Test.
Fuse.
Warning. Refer to the Operating Manual.
Conforms to Standards of European Union.

Model UT50A/B/C: OPERATING MANUAL

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The multimeter Structure (see figure 1)

9

( figure 1)

1 LCD Display
2 Data Hold Button.
3 Rotary Switch
4 Other Input Terminals
5 COM Input Terminal
6 20A Input Terminal

7 The Model UT50A:µAmA Input terminal
The Model UT50B/UT50C:mA Input terminal

8 Power

Model UT50A/B/C: OPERATING MANUAL

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Functional Buttons

Button Operation Performed

Turn the Meter on and off.
l Press down the POWER to turn
on the Meter.
l Press up the POWER to turn off
the Meter.

HOLD

(Blue Button)

l Press HOLD once to enter hold
mode.
l Press HOLD again to exit hold
mode.
l In Hold mode, is displayed and
the present value is shown.

POWER

(Yellow Button)

Below table indicated for information about the functional
button operations

Model UT50A/B/C: OPERATING MANUAL

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Display Symbols (see figure 2)

( figure 2)

No. Symbol Meaning

1

Dangerous Voltages.

2

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.

3

Indicator for AC voltage or
current.The displayed value is the
mean value.

4

Indicates negative reading.

5

Test of diode.

6

Data hold is active.

7

The continuity buzzer is on.

8

Centigrade temperature

o

C

o

F

9

Fahrenheit temperature

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.

10

V: Volts. The unit of voltage.
mV: Millivolt. 1 x 10-3 or 0.001 volts.

mV, V

11

Model UT50A/B/C: OPERATING MANUAL

10-14

12

Display Symbols (see figure 2)

No. Symbol Meaning

nF, µF

12

F: Farad. The unit of capacitance.
µF: Microfarad.1 x 10

-6

or 0.000001
farads.
nF: Nanofarad. 1 x 10-9 or 0.000000001
farads.

kHz

13

The unit of frequency in cycles/
second. Kilohertz. 1 x 10-3 or

1,000 hertz.

Ω: Ohm. The unit of resistance.
kΩ: kilohm. 1 x 103 or 1000

ohms.
MΩ: Megaohm. 1 x 106 or 1,000,000

ohms.

Ω,kΩ,MΩ

14

Model UT50A/B/C: OPERATING MANUAL

Measurement Operation(1)

A. DC 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 or 750V rms although
readings may be obtained.

The DC Voltage ranges are: 200mV, 2V, 20V, 200V and
1000V. To measure DC voltage, connect the Meter as
follows:

( figure 3)

13

1. Insert the red test lead into the VΩ input terminal
and the black test lead into the COM input 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.

l Make sure the Sleep Mode is not on if you found
there is no display on the LCD after turning on the
Meter.
l Make sure the Low Battery Display is not on, otherwise
false readings may be provided.
l Pay extra attention to the

symbol which is located
besides the input terminals of the Meter before carrying
out measeurement.

red black

Model UT50A/B/C: OPERATING MANUAL

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Measurement Operation(2)

Note

l If the value of voltage to be measured is unknown,
use the maximum measurement position (1000V)
and reduce the range step by step until a satisfactory
reading is obtained.
l The LCD displays “1” indicating the existing selected
range is overloaded, it is required to select a higher
range in order to obtain a correct reading.
l In each range, the Meter has an input impedance of
approx. 10MΩThis 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.

B. AC Voltage Measurement (see figure 4)

Warning
To avoid harms to you or damages to the Meter from
electric shock, please do not attempt to measure
voltages higher than 1000V or 750V rms although
readings may be obtained.

( figure 4)

red black

Model UT50A/B/C: OPERATING MANUAL

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The Model UT50A: The AC voltage measurement has

5 measurement positions on the rotary switch: 200mV,
2V, 20V, 200V and 750V
The Model UT50B/UT50C: The AC voltage measurement
has 4 measurement positions on the rotary switch: 2V,
20V, 200V and 750V

To measure AC 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 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 unknown,
use the maximum measurement position (750V) and
reduce the range step by step until a satisfactory
reading is obtained.

l The LCD displays “1” indicating the existing selected
range is overloaded, it is required to select a higher
range in order to obtain a correct reading.
l In 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 AC voltage measurement has been completed,
disconnect the connection between the testing leads
and the circuit under test.

Measurement Operation(3)

Model UT50A/B/C: OPERATING MANUAL

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Measurement Operation(4)

C. DC Current Measurement (see figure 5)

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 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.

The Model UT50A: The DC current measurement has

4 measurement positions on the rotary switch: 20µA,
2mA, 200mA and 20A.
The Model UT50B: The DC current measurement has
4 measurement positions on the rotary switch: 2mA,
20mA, 200mA and 20A.
The Model UT50C: The DC current measurement has
3 measurement positions on the rotary switch: 20mA,
200mA and 20A.

To measure current, do the following:

1. Turn off power to the circuit. Discharge all high­ voltage capacitors.

( figure 5)

red

black

Model UT50A/B/C: OPERATING MANUAL

2. Insert the red test lead into the µAmA (The Model

UT50B/UT50C) or 20A terminal and the black test

lead into the COM terminal.

3. Set the rotary switch to an appropriate measurement
position in A range.

4. Break the current 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 (20A) and
20A terminal, and reduce the range step by step until
a satisfactory reading is obtained.
l When current measurement has been completed,
disconnect the connection between the testing leads
and the circuit under test.

D. AC Current Measurement (see figure 6)

( figure 6)

17

red

black

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Measurement Operation(6)

Warning
Never attempt an in-circuit current measurement
where the voltage between terminals and ground is
greater than 60V.
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.

The Model UT50A: The AC current measurement has

5 measurement positions on the rotary switch: 200µA,
2mA, 20mA, 200mA and 20A.
The Model UT50B/UT50C: The AC current measurement
has 3 measurement positions on the rotary switch: 20mA,
200mA and 20A.

Note

l If the value of current to be measured is unknown,
use the maximum measurement position (20A) and
20A terminal and reduce the range step by step until
a satisfactory reading is obtained.
l When current measurement has been completed,
disconnect the connection between the testing leads
and the circuit under test.

To measure current, do the following:

1. Turn of f power to the circuit.Discharge all high-voltage
capacitors.

2. Insert the red test lead into the µAmA (The Model

UT50A) or mA (The Model UT50B/UT50C) or 20A
terminal and the black test lead into the COM terminal.

3. Set the rotary switch to an appropriate measurement
position in A range.

4. Break the current 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.

Model UT50A/B/C: OPERATING MANUAL

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E. Measuring Resistance (see figure 7)

Warning
T o avoid damages to the Meter or to the devices under
test, disconnect circuit power and discharge all the
high-voltage capacitors before measuring resistance.

The resistance ranges are:
The Model UT50A/UT50B: 200Ω, 2kΩ, 20kΩ, 200kΩ,

2MΩ, 20MΩand 200MΩ.
The Model UT50C: 200Ω, 2kΩ, 20kΩ, 200kΩ, 2MΩ
and 200MΩ.

To measure resistance, 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 inΩ range.

3. Connect the test leads across with the object being
measured.The measured value shows on the display .

Note

l The test leads can add 0.1Ωto 0.3Ω of error to the
resistance measurement.To obtain precision readings
in low-resistance, that is the range of 200Ω, short­ 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:

Measurement Operation(7)

( figure 7)

red black

Model UT50A/B/C: OPERATING MANUAL

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measured resistance value (Y) – (X) = precision
readings of resistance.
l For high resistance (>1MΩ), it is normal
taking several seconds to obtain a stable reading.
l When there is no input, for example in open circuit
condition, the Meter displays “1”.
l When resistance measurement has been completed,
disconnect the connection between the testing leads
and the circuit under test.

Measurement Operation(8)

F. The Model UT50C: Frequency Measurement (see figure 8)

Warning
To avoid harm to you or damages to the Meter, do
not attempt to measure voltages higher than 60V in
DC or 30V rms in AC although readings may be
obtained. When the frequency signal to be tested is
higher than 30V rms, the Meter cannot guarantee
accuracy of the measurement.

( figure 8)

red black

The frequency measurement ranges are 2kHz and 20kHz.
To measure frequency, 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 kHz range.

3. Connect the test leads across with the object being
measured.
The measured value shows on the display.

Model UT50A/B/C: OPERATING MANUAL

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Note

l When Hz measurement has been completed,
disconnect the connection between the testing leads
and the circuit under test.

G. The Model UT50B/UT50C: Temperature
Measurement (see figure 9)

Warning
To avoid harm to you or damages to the Meter, do
not attempt to measure voltages higher than 60V in
DC or 30V rms in AC although readings may be
obtained.

The temperature measurement range is from -40 oC~
1000 oC or -40 oF~1832 oF. To measure temperature,
connect the Meter as follows:

Note

l The Meter automatically displays the temperature
value inside the Meter when there is no temperature
probe connection.

Measurement Operation(9)

1. Insert the red temperature into the VΩ terminal
and the black temperature probe into the COM terminal.

2. Set the rotary switch to oC or oF.

3. Place the temperature probe to the object being
measured.
The measured value shows on the display.

( figure 9)

Model UT50A/B/C: OPERATING MANUAL

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l The included temperature probe can only be measured
up to 250oC For any mesaurement higher than that,
the rod type temperature probe must be used instead.
l When temperature measeuremnet has been completed,
disconnect the connection between the testing leads
and te circuit under test.

Measurement Operation(10)

H.Capacitance Measurement (see figure 10)

( figure 10)

The Model UT50A:Capacitance measurement has
4 measurement positions on the rotary switch : 2nF, 20nF,
2µF and 100µF.
The Model UT50B/UT50C: Capacitance measurement
has 4 measurement positions on the rotary switch: 20nF,
200nF, 2µF and 100µF.

To measure capacitance, connect the Meter as follows:

1. Insert the red test clip or red test lead into the VΩ
terminal and the black test clip or black test lead into
the µmA (The Model: UT50A) or mA (The Model:
UT50B/UT50C) terminal.

2. Set the rotary switch to an appropriate measurement
position in Fcx range.

3. Connect the test leads across with the object being
measured.
The measured value shows on the display.

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Measurement Operation(11)

Note

l For testing the capacitor with polarity, connect the
red test lead to anode & black test lead to cathode
l When the tested capacitor is shorted or the capacitor
value is overloaded, the LCD display “1”.
l To minimize the measurement error caused by the
distributed capacitor, the testing lead or testing clip
should be as short as possible.

When the tested capacitor is greater than 30 µF,
reading is for reference only.

l It is normal to take a while for zeroing when changing
over the measurement range. This process will not
affect the accuracy of the final readings obtained.

I. Measuring Diodes & Continuity

Warning
To avoid damage to the Meter or to the equipment
under test, disconnect circuit power and discharge
all high-voltage capacitors before measuring diodes
and continuity .

Testing Diodes
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.

To test out 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’s
anode and place the black test lead on the component’s
cathode.
The measured value shows on the display.

Model UT50A/B/C: OPERATING MANUAL

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Measurement Operation(12)

Note

l In a circuit, a good diode should still produce a forward
voltage drop reading of 0.5V to 0.8V; however; the
reverse voltage drop reading can vary depending on
the resistance of other pathways between the probe
tips.
l Connect the test leads to the proper terminals as said
above to avoid error display. The LCD will display
“1” indicating open-circuit for wrong connection.
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.

Testing for Continuity
To test for continuity, connect the Meter as below:

1. Insert the red test lead into VΩ 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 buzzer sounds if the resistance of a circuit under
test is less than 70Ω .
The LCD displays the resistance value of a circuit under
test.

Note

l The LCD display “1” indicating the circuit being
tested is open.
l When continuity testing has been completed,
disconnect the connection between the testing leads
and the circuit under test.

Model UT50A/B/C: OPERATING MANUAL

Sleep Mode

25

Turning on the Auto Display Backlight

The Meter has a built-in sensor. Therefore the Display
Backlight turns on and off automatically depending on
the brightness of the environment. In a dim condition,
the Display Backlight turns on automatically while in a
bright condition, the Display Backlight turns off automatically .

Model UT50A/B/C: OPERATING MANUAL

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General Specifications

l Maximum voltage between

any Terminals and

Grounding : 1000V rms.

l

Fused Protection for
mA Input Terminal : 0.5A, 250V fast
type, 5x20mm.

l

Fused Protection for 20A
Input Terminal : Un-fused.

l Range : Manual ranging.
l Maximum Display : Display :1999.
l Mesaurement Speed : Updates 2~3 times/second.
l Temperature : Operating: 0oC~40oC

(32oF~104oF);
Storage : -10oC~50oC( 14oF~122oF).
l Relative Humidity :

75% @ 0oC~30oC;

50% @ 31oC~40oC.
l Altitude: Operating : 2000m;
Storage : 10000m.
l Battery Type : 9V NEDA1604 or 6F22
or 006P.

l Battery Deficiency : Display “

”.

l Data Holding : Display “

”

l Negative reading : Display “ “
l Overloading : Display “1”.
l Dimensions (HxWxL) : 165x80x38.3mm.
l Weight : Approx.275g (battery

included).
l Safety/Compliances : IEC61010 CAT II 1000V
overvoltage and double
insulation standard.
l Certificate :

Model UT50A/B/C: OPERATING MANUAL

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Accuracy Specifications(1)

Accuracy: (a% reading + b digits),guarantee for 1 year.
Operating temperature:23oC

5oC.

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

A. DC Voltage

Remark: Input impedance: 10MΩ
B. AC Voltage

200mV

2V

20V
200V
750V

Remarks:

l Input impedance: 10MΩ .
l Frequency response: 40Hz~400Hz.
l Display effective value of sine wave (mean value

response).

200mV

2V

20V

200V

1000V

100µV

1mV

10mV

100mV

1V

Range Resolution

(0.5%+1)

Overload
Protection

UT50A UT50B UT50C

Accuracy

250VDCor
ACrms.

(0.8%+2)

1000V DC
or 750V AC
rms.

100µV

1mV

10mV

100mV

1V

Range

Resolution

(1.2%+3)

Overload
Protection

UT50A UT50B UT50C

Accuracy

250V DC or
AC rms

(0.8%+3)
(1.2%+3)

1000V DC
or 750V
AC rms.

Model UT50A/B/C: OPERATING MANUAL

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Accuracy Specifications(2)

C. DC Current

Range

Resolution

(0.8%+1)

Overload
Protection

UT50A UT50B UT50C

Accuracy

(2%+5)

20µA

2mA

20mA

200mA

20A

0.01µA
1µA

10µA

100µA

10mA

(0.8%+1)

(0.8%+1)

0.5A. 250V
fast type

fuse, 5x20
mm

Un-Fused

(1.5%+1)

Remarks:

l At 20A Range: For continuous measurement

10

seconds and interval not less than 15 minutes.

l Measurement voltage drop: Full range at 200mV.
D. AC Current

Range

Resolution

(1%+3)

Overload
Protection

UT50A UT50B UT50C

Accuracy

(3%+5)

(1.8%+3)

200µA

2mA

20mA

200mA

20A

0.1µA
1µA

10µA

100µA

10mA

(1%+3)

0.5A. 250V
fast type

fuse, 5x20
mm

Un-Fused

Remarks:

l At 20A Range: For continuous measurement

10

seconds and interval not less than 15 minutes.

l Measurement voltage drop: Full range at 200mV.
l Frequency reaponse: 40Hz~400Hz
l Display effective value of sine wave (mean value

response).

Model UT50A/B/C: OPERATING MANUAL

29

E. Resistance Test

Accuracy Specifications(3)

200Ω

2kΩ

20kΩ

200kΩ

2MΩ

20MΩ

200MΩ

Range

Resolution

(0.8%+3)

Overload
Protection

UT50A UT50B UT50C

Accuracy

(1%+2)

0.1Ω
1Ω

10Ω

100Ω

1kΩ

10kΩ

100kΩ

[5%(reading-10)+10]

250V DC

or AC rms

(0.8%+1)

Remarks:

l Open circuit voltage:

700mV (At 200MΩ range,
it is approx. 2.8V)
l At 200MΩ range , test lead is in short circuit , and it
is normal to display 10 digits. During measurement,
subtract the 10 digits from the reading.

F. The Model UT50C: Frequency

Remarks: Input Sensitivity: 200mV.

G. The Model UT50B/UT50C: Temperature

Range

Resolution

(3%+3)

Overload
Protection

UT50B UT50C

Accuracy

250V AC

-40oC~0oC

0oC~400oC

400oC~1000oC

-40oF~32oF

32oF~752oF

752oF~1832oF

(1%+3)

2.5%
(3%+4)
(1%+4)

(1.5%+15)

1oC

1oF

1Hz

10Hz

Range Resolution Accuracy Overload Protection

2kHz

20kHz

(2%+5)

(1.5%+5)

250V AC

Model UT50A/B/C: OPERATING MANUAL

30

Accuracy Specifications(4)

Range

Resolution

(4%+3)

Overload
Protection

UT50A UT50B UT50C

Accuracy

(4%+3)

H. Capacitance

2nF

20nF

200nF

2µF

100µF

1pF

10pF

0.1nF
1nF

0.1µF

(5%+4)

(4%+3)

250V AC

Remarks:Testing signal:approx. 400Hz 40mV rms.
When the tested capacitor is greater than 30 µF,
reading is for reference only.

I. Diodes and Continuity Test

1mV

1Ω

Range Resolution Input Protection Remark

Open circuit
voltage approx.2.8V

250V DC or AC

<70Ωbuzzer beeps
continuously

Model UT50A/B/C: OPERATING MANUAL

31

Maintenance(1)

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
not get water inside the case.

A. General Service

l Periodically wipe the case with damp cloth and mild
detergent. Do not use chemical solvent.
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 place of humidity, high
temperature, explosive, inflammable and strong
magnetic field

B. Replacing the Battery (see figure 11)

(figure 11)

Model UT50A/B/C: OPERATING MANUAL

32

Maintenance(2)

Warning

T o avoid false readings, which could lead to possible
electric shock or personal injury ,replace the battery

as soon as the battery indicator appears.

To replace battery:

1. 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.

2. Turn the Meter OFF

3. Remove the rubber feet and screws from the battery
compartment, and separate the battery compartment
from the case bottom

4. Remove the battery from the battery compartment.

5. Replace the battery with a new 9V battery (NEDA
1604 or 6F22 or 006P).

6. Rejoin the battery compartment and the case bottom,
and install the screw and rubber feet

C. Replacing the Fuses

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. 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.

2. Turn the Meter OFF.

3. Remove the rubber feet and screws from the case
bottom, and separate the case bottom from the case
top.

4. Remove the fuse by gently prying one end loose,
and then take out the fuse from its bracket.

Model UT50A/B/C: OPERATING MANUAL

33

Model UT50A/B/C: OPERATING MANUAL

Maintenance(3)

1. Install ONLY replacement fuses with the identical
type and specification as follows and make sure the
fuse is fixed firmly in the bracket. 0.5A. 250V fast
type fuse, φ 5x20mm.

2. Rejoin the case bottom and the case top, and install
the screw and rubber feet
Replacement of fuses is seldom required. Burning of a
fuse always results from the improper operation.

~ END ~

This operating manual is subject to change without notice.

34

Manufacturer: UNI-TREND TECHNOLOGY(DONG GUAN)LIMITED
Address: Dong Fang Da 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: [phone]
Fax: [phone]
Email: [e-mail]
http://www.uni-trend.com

Copyright 2001 Uni-Trend International Limited.

All rights reserved.

Model UT50A/B/C: OPERATING MANUAL