E. Continuity Measurement
Range Resolution Remark
Open Circuit Voltage around
-1.2V;Buzzer beeps at resistance
≤10Ω; Buzzer not sound when
resistance > 70Ω;
F. Diodes Measurement
Range
Resolution Ove
rload Protection
1mV 300Vr
ms
Remark: Open Circuit Voltage around 3V, Displays
approximate forward voltage drop.
G. Capacitance
Range Reso
lution Accuracy Overload Protection
3nF 0.001nF
30nF
0.01nF
300nF
0.1nF
3μF
1nF
30μF
10nF
300μF
100nF
±(5%+5)
3mF
reference
Remarks:
1. Under auto scan mode the max range is 300μF.
2. There is a residual reading when the circuit is open.
To measure a small value of capacitance, subtract it
to ensure accuracy.
Maintenance
(see figure 4)
This section provides basic maintenance information
and battery replacement instruction.
Figure 4
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 bar with
detergent, as dirt or moisture in the terminals can
affect readings.
● Turn the Meter off when it is not use and take out
the battery when not using 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:
1. 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.
2. Remove the screw from battery compartment and
separate the battery compartment from the case
bottom.
3. Remove the battery from the battery compartment.
4. Replace the battery with a new 3V battery
5. Rejoin the case bottom and the battery
compartment, and reinstall the screw.
UT118A/B
Operating Manual
Development District,Hu Men Town,Dong Guan Cit
y,
Guang Dong Province,China
3. 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
V .
● Press
SELECT
to select AC voltage measurement
mode
● Connect the test leads across with the object being
measured. The measured value shows 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.
4. 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
V 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.
5. auto measurement
Warning
To avoid damages to the Meter or to the devices
under test, disconnect circuit power and discharge all
the high-voltage capacitors before measurement.
● Set the switch to .
● Auto measuremeng mode is a default, under this
mode can measure Resistance, Diode, Continuity
and Capacitance automatically.
● For better accuracy, it better 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: <15Ω or >10MΩ
Capacitance: <400pF or >1mF
Will get an irresponsible value.
6. Resistance Measurement
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 measure resistance, do the following:
● Set he rotary switch to .
● Press
SELECT
to select
Ω
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.
7
. Continuity Test
Warning
To avoid damages to the Meter or to the devices
under test, disconnect circuit power and discharge all
the high-voltage capacitors before continuity test.
To measure resistance, do the following:
● Set he rotary switch to .
● Press SELECT to select measurement mode.
● Connect the test leads across with the object being
measured.
● The buzzer sounds continuously if the resistance
of a circuit under test is≤30Ω, 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
8. Diodes Test
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 diodes.
To measure diode, do the following:
● Set he rotary switch to .
● Press SELECT to select measurement mode
● For better accuracy, it better separate the object
being measured from the circuit before
measurement.
● When diodes measurement has been completed,
disconnect the connection between the testing
leads and the circuit under test.
9. Capacitance Measurement
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:
● Set he rotary switch to .
● Press SELECT to select measurement mode
● For better accuracy, it better separate the object
being measured from the circuit before
measurement.
● When diodes measurement has been completed,
disconnect the connection between the testing
leads and the circuit under test.
General Specifications
● Maximum voltage between red Terminals and
Grounding: 300Vrms.
● Maximum Display: 3000. Updates 4 times/second
● Temperature:
Operating: 0
℃
~40
℃
(32
℉
~104
℉
);
Storage: -10
℃
~50
℃
( 14
℉
~122
℉
).
● Relative Humidity: ≤75% @ 0
℃
~30
℃
;
≤ 50% @ 31
℃
~40
℃
● Altitude: Operating: 2000m; Storage: 10000m.
● Battery Type: 3V Li-MnO2 Button cell battery
● Battery Deficiency: Display “ ”.
● Dimensions (HxWxL): 20.18x26.5x181.5mm
● Weight: Approx.90g (battery included).
Accuracy Specifications
Accuracy:±(a% b digits)guarantee for 1 year.
Operating temperature: 18
℃
~ 28
℃
.
Relative humidity: <75%.
A . AC Voltage
Range
Resolution Accuracy
Overload Protection
3V
0.001V
30V
0.01V
± (1%+4) 300Vrms
300V
0.1V
Remark: Input Impedance: ≥10MΩ
Frequency Response: 40Hz ~ 400Hz
B. DC Voltage
Ran
ge Resolution Accuracy
Overload Protection
3V
0.001V
30V
0.01V ± (1%+3) 300Vrms
300V
0.1V
Remark: Input Impedance: ≥10MΩ
C. EF Test (UT18B Only)
Range
Remarks
<10mm: buzzer beeps;
220V/50H 10~50mm: may and may not beeps;
>50mm: Buzzer not sound
D. Resistance
Range
Resolution Accuracy
Overload Protection
300Ω
0.1Ω
3kΩ
1Ω
30kΩ
10Ω
300kΩ
100Ω
300Vrms
3MΩ
1kΩ
30MΩ
10kΩ
Remark: Under auto scan mode the max range is
3MΩ.
± (1%+3)
± (1.5%+5)
±(3%+5)
300Vrms
0.1 Ω
