UNI-T UT118A Pen Type Meters User Manual

: June 1, 2024
: UNI-T

Table of Contents

UNI-T UT118A Pen Type Meters
Overview
Unpacking Inspection
Safety Information And Safe Operation
International Electrical Symbols
Button function and power
Measurement Operation
AC Voltage Measurement
Resistance Measurement
Diodes Test
Capacitance Measurement
Specifications
- General Specifications
- Accuracy Specifications
Maintenance
Contact
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UNI-T UT118A Pen Type Meters

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 UT118A and UT118B (hereafter referred to as “the Meter”) are 3000 counts pen type digits millimetres. The Meter uses a large scale of integrated circuit with a professional multimeter IC as its core and has full range overload protection.

The Meter measures or tests the following:

AC/DC voltage
EF Function (UT118B only)
Resistance
Diode
Continuity
Capacitance

Unpacking Inspection

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

Item	Description	Qty
1	English Operating Manual	1 piece
2	Test Lead	1 pair

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

Safety Information And Safe Operation

Safety Information

This Meter complies with standards EN61010: in pollution degree 2, overvoltage category (CATIII 300V) and double insulation.
CATIII : 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 the user should pay attention on.

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:

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 numbers or electrical specifications before using the Meter.
When using the test leads, keep your fingers behind the ﬁnger guards.
Do not apply more than the rated voltage, as marked on the Meter, between the terminals or between any terminal and grounding.
When the Meter working at an effective voltage over 60V DC or 30V AC, special care should be taken for there is danger of electric shock.
Use the proper function, and range for your measurements.
Disconnect circuit power and discharge all high-voltage capacitors before testing current, resistance, diodes or continuity.
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.
When servicing the Meter, use only the same model 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.
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.

International Electrical Symbols

The Meter Structure (see ﬁgure 1)

Front Housing
Functional buttons
Switch
LCD Display
Input Terminals

Display Symbols (see Figure 2)

Indicates auto scan mode
High voltage indicator
Data hold is active
Indicates negative reading
The meter is in the auto-range mode
Indicator for AC voltage
Indicator for DC voltage
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.
Minimum reading.
Maximum reading.
The unit of Capacitance
Test of diode
The continuity buzzer is on.
V: Volts. The unit of voltage.
mV: Millivolt. 1×10(-3) or 0.001 volts.
Ω: Ohm. The unit of resistance
kΩ: kilohm. 1×10 (3) or 1000 ohms.
MΩ: Megaohm. 1×10 or 1,000,000 ohms

Button function and power

Button function and auto power off

SELECT
Press SELECT to switch between resistance, AC/DC voltage, continuity buzzer and diode measurement modes. Press and hold for more than 2 seconds in or exit “sleep” mode.
HOLD
- Press HOLD to enter and exit hold mode (except under auto scan mode).
- Press and hold the HOLD button for more than 2 seconds, and the meter automatically holds the value obtained at 6 seconds later, at this time, H is displayed and ﬂickering.
- If enter “sleep” mode under hold mode, the meter is still in the hold mode when it is turned on.
MAX/MIN
The MAX/MIN mode stores minimum (MIN) and maximum (MAX) input values (except under auto scan mode). Manual ranging comes when you select this function.
Press the MAX/MIN button and vice versa.
Under hold mode and max/min mode, should exit hold mode ﬁrst then press and hold MAX/MIN more than 1 second to exit max/min mode.
Display Backlight and test lead light button, Press once to turn the display backlight and test lead light on and press again to turn the display backlight and test lead light off. It will automatically off after around 1 minute.
AUTO POWER OFF
To preserve battery life, the Meter automatically goes into “sleep” mode if you do not press any button for around 10 minutes. The Meter can be activated by pressing any button, then returns to the display for the function selected previously
BUZZER
The buzzer phonate goes with every time the button is effectually pressed. When the meter will auto power off in 20 seconds the buzzer beeps three times. Before the power is off there will be a long time buzzer beeps.

Measurement Operation

Before measurement, anticlockwise circumgyrate the red cover and rock the input terminal.
When all the measurements have been completed, deasil circumgyrate the red cover then hide the input terminal. (see ﬁgure 3)

AC / DC Voltage auto Measurement.

Warning

To avoid harm to the Meter, never input higher than 300V voltage although it is possible to measure higher voltage.
To measure Voltage, connect the Meter as follows:
Set the switch to
Auto measurement mode is a default. Under this mode can measure AC voltage and DC voltage.
Connect the test leads across with the object being measured. The measured value shown on the display.
When 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 terminal of the meter. .

Note:
The threshold voltage of AC voltage is around 400mV.

DC Voltage Measurement

Warning
To avoid harm to the Meter, never input higher than 300V voltage although it is possible to measure higher voltage.

Set the switch to .
Press SELECT to select DC voltage measurement mode.
Connect the test leads across with the object being measured. The measured value is shown on the display.
When 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 terminal of the meter.

AC Voltage Measurement

Warning
To avoid harm to the Meter, never input higher than 300V voltage although it is possible to measure higher voltage.

Set the switch to .
Press SELECT to select the AC voltage measurement mode
Connect the test leads across with the object being measured. The measured value is shown on the display.
When 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 terminal of the meter.

Note:

The threshold voltage of AC voltage is around 400mV.
EF Measurement UT118B only)

Warning: To avoid harm to the Meter, never input higher than 300V voltage although it is possible to measure higher voltage.

Set the switch to EF and remove the test lead from the input terminal.
Press SELECT to select EF measurement mode.
Unconnected measurement. Place the red terminals towards the object being measured.

Hf auto measurement
Warning: To avoid damage to the Meter or to the devices under test, disconnect the circuit power and discharge all the high-voltage capacitors before measurement.

Set the switch to .
Auto measurement mode is a default, under this mode can measure Resistance, Diode, Continuity and Capacitance automatically.
For better accuracy, it is better to separate the object being measured from the circuit before measurement.
When voltage measurement has been completed, disconnect the connection between the testing leads and the circuit under test.

Note:

Under auto measurement mode, when input:
Resistance: <15Q or >10MQ
Capacitance: <400pF or >1mF Will get an irresponsible value

Resistance Measurement

To avoid damage to the Meter or the devices under test, disconnect the circuit power and discharge all the high-voltage capacitors before measuring resistance.

To measure resistance, do the following:

Set the rotary switch to .
Press SELECT to select Q measurement mode.
Connect the test leads across with the object being measured.
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.

Continuity Test

Warning: To avoid damage to the Meter or the devices under test, disconnect the circuit power and discharge all the high-voltage capacitors before the continuity test. To measure resistance, do the following:

Set the rotary switch to .
Press SELECT to select measurement mode.
Connect the test leads across with the object being measured.
The buzzer sounds continuous if the resistance of a circuit under test is<30O, it indicates the circuit is in good connection.

Note: When continuity 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

Diodes Test

Warning
To avoid damage to the Meter or to the devices under test, disconnect the circuit power and discharge all the high-voltage capacitors before measuring diodes. To measure the diode, do the following:

Set the rotary switch to Hf .
Press SELECT to select -H- measurement mode For better accuracy, it better separates the object being measured from the circuit before measurement.
When the diode measurement has been completed, disconnect the connection between the testing leads and the circuit under test.

Capacitance Measurement

Warning: To avoid damage to the Meter or 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:

Set the rotary switch to .
Press SELECT to select the Hf measurement mode
For better accuracy, it is better to separate the object being measured from the circuit before measurement.
When the diode measurement has been completed, disconnect the connection between the testing leads and the circuit under test.

Specifications

General Specifications

Maximum voltage between red Terminals and Grounding: 300Vrms.
Maximum Display: 3000. Updates 4 times/second Temperature:
- Operating : 0°C~40°C (32°F~104°F);
- Storage: -10°C~50°C( 14°F~122°F).
Relative Humidity: <75% @ 0°C~30°C ; < 50% @ 31°C~40°C
Altitude: Operating: 2000m; Storage: 10000m.
Battery Type: 3V Li-Mn02 Button cell battery
Battery Deficiency: Display “
Dimensions (HxWxL): 20.18×26.5×181.5mm
Weight: Approx .90g (battery included).

Accuracy Specifications

Accuracy: ±(a% reading+b digits)guarantee for 1 year.
Operating temperature: 18°C ~ 28°C.
Relative humidity: <75%.

A . AC Voltage

Remark: Input Impedance: >10MO
Frequency Response : 40Hz ~ 400Hz

B. DC Voltage

Remark: Input Impedance: >10MO

C. EF Test (UT118B Only)

D. Resistance

Remark: Under auto scan mode the max range is 3MO.

E. Continuity Measurement

F. Diodes Measurement

Remark: Open Circuit Voltage around 3V, Displays approximate forward voltage drop

G. Capacitance

Remarks:

Under auto scan mode the max range is 300pF.
There is a residual reading when the circuit is open.
To measure a small value of capacitance, subtract it to ensure accuracy

Maintenance

Maintenance (see figure 4)
This section provides basic maintenance information and battery 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

Periodically wipe the case with a damp cloth and mild detergent. Do not use abrasives or solvents.
To clean the terminals with cotton bars with detergent, as dirt or moisture in the terminals can affect readings.
Turn the Meter off when it is not used and take out the battery when not used for a long time.
Do not store the Meter in a place of humidity, high temperature, explosive, inflammable and strong magnetic field.

B. Replacing the Battery

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.

To replace the battery:

Turn the Meter off. 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.
Remove the screw from the battery compartment and separate the battery compartment from the case bottom.
Remove the battery from the battery compartment.
Replace the battery with a new 3V battery
Rejoin the case bottom and the battery compartment, and reinstall the screw.