UNI-T UT90A Operating Manual

Table of Contents

Title Page

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 Voltage Measurement
B. AC Voltage 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

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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 Safe Operation"
carefully before 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
icons display, full overload protection and streamline
outlook.

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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.

Holster

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Item

1
2

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Description

English Operating Manual
Test Lead

9V Battery (NEDA 1604, 6F22 or 006P)

Qty

1 piece

1 pair
1 piece
1 piece

Safety Information

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

CA T.II: Local level, appliance, PORTABLE EQUIPMENT
etc., with smaller transient overvoltages than CAT. III
CAT.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.

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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 When using the test leads, keep your fingers
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 in the right
position and no any changeover of range shall
be made during measurement is conducted to
prevent damage of the Meter.
l Disconnect circuit power and discharge all high­ voltage capacitors before testing current,
resistance, diodes or continuity.

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.

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Rules For Safe Operation (2)

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 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 temperature, humidity, explosive,
inflammable and strong magnetic field. The
performance of the Meter may deteriorate after
dampened.
l The Meter is suitable for indoor use.

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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.
Fuse.
Warning. Refer to the Operating Manual.
Conforms to Standards of European Union.

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The Meter Structure (see figure 1)

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( figure 1)

1 LCD Display.
2 Hold Button.
3 Rotary Switch.
4 Input Terminals.
5 Power Button.

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AC Current Measurement Range from

0.1µA to 10A

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Functional Buttons

Below table indicated for information 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