UNI-T UT58A Operating Manual

Overview
Warning
To avoid electric shock or personal injury, read the
"Safety Information", carefully before using the Meter.
Digital Multimeters Model UT58A, UT58B and UT58C
are 2000-count hand-held instruments with remarkable
features: ex-large LCD, steady operations, overload
protection for all ranges and unique structure. The
Meter can measure AC/DC voltage, AC/DC current,
resistance, capacitance, temperature, frequency,
transistor, diode and continuity, and is equipped with
data hold, full icon display and sleep mode functions.
Unpacking Inspection
for
Item Description Qty
1 English Operating Manual 1 pc
2 Test Lead 1 pair
3 Multi-Purpose Socket 1 pc
4 Point Contact Temperature Probe 1 pc
(UT58B/UT58C only)
5 9V Battery (NEDA 1604, 6F22 or 009P) 1 pc
In the event you find any missing or damaged part,
please contact your dealer immediately.
Safety Information
This Meter complies with the standards IEC61010:
Pollution Degree2, Overvoltage Category (CAT. II 1000V,
CAT. III 600V) and Double Insulation.
CAT. II: Local level, appliance, PORTABLE EQUIPMENT
etc., with smaller transient voltage 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 to.
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
number or electrical specifications before using
the Meter.
Do not apply more than the rated voltage, as
marked on the Meter, between the terminals or
between any terminal and grounding.
The rotary switch should be placed in the right
position and no any changeover of range shall
be made during measurement to prevent damage
of the Meter.
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.
Use the proper terminals, function, and range
for your measurements.
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.
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.
When using the test leads, keep your fingers
behind the finger guards.
Disconnect circuit power and discharge all high
-voltage capacitors before testing resistance,
continuity, diodes, capacitance or current.
Before measuring current, check the Meter's
fuses and turn off power to the circuit before
connecting the Meter to the circuit.
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.
Remove test leads, test clips and temperature
probe from the Meter and turn the Meter power
off before opening the Meter case.
When servicing the Meter, use the replacement
parts with the same model or identical electrical
specifications.
To avoid any damage to the meter or any accident,
do not alter the internal circuit of the Meter randomly.
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.
The Meter is suitable for indoor use.
Turn the Meter power off when it is not in use
and take out the battery when not using for a long
time.
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.
International Electrical Symbols
AC (Alternating Current).
DC (Direct Current).
Grounding.
Double Insulated.
Low Battery Indication.
Warning. Refer to the Operating Manual.
Conforms to Standards of European Union.
The Meter Structure
(See Figure 1)
1. LCD Display.
2. HOLD Button.
3. Rotary Switch.
4. Input Terminals.
5. POWER
(Figure 1)
Transistor Test
Functional Buttons
Below table indicated for information about the functional
button operations.
Button Description
POWER Turn the Meter on and off.
(Yellow
Press down the POWER to turn on
Button)
the Meter.
Press up the POWER to turn off the
Meter.
Press HOLD once to enter hold mode.
HOLD
Press HOLD again to exit hold mode.
(Blue
In Hold mode, is displayed and the
Button)
present value is shown.
(See Figure 2)
Ω Ω Ω
CmVV k M
μ μ
nF FkHz AmAA
Connect Test Leads
μ Ω
A AmA V
COM
(Figure 2)
No. Symbol Description
1 The unit of transistor test
The battery is low.
2
Warning: To avoid false
readings, replace the battery as
soon as the battery indicator
appears.
Indicator for AC voltage or current.
3
The displayed value is the mean
AC
value.
4
Indicates negative reading.
5 Test of diode.
6 The continuity buzzer is on.
Date hold is active.
7
8 Indicator of connecting test leads
Connect
into different input terminals.
Terminal
Ω,kΩ,MΩ
mV, V
μF nF
9
μA, mA, A
o
C
Measurement Operation
A. Measuring DC and AC Voltage (See Figure 3)
black red
(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.
The DC Voltage ranges are: 200mV, 2V, 20V, 200V and
1000V.
The AC Voltage ranges are: 2V, 20V, 200V and 750V
To measure DC or AC Voltage, connect the Meter as follows:
1. Insert the red test lead into the HzVΩ (UT58C) or
VΩ (UT58A/UT58B) terminal and the black test
lead into the COM input terminal.
2. Set the rotary switch to an appropriate measurement
position in V or V range.
3. Connect the test leads across with the object to be
measured.
The measured value shows on the display.
B. Measuring DC and AC Current (See Figure 4)
black red
(figure 4)
Warning
Never attempt an in-circuit current measurement
where the open circuit voltage between terminals
and ground is greater than 250V .
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 DC Current ranges are:
Model UT58A/ UT58B: 20μA,2mA,20mA,200mA and 20A.
Model UT58C: 2mA, 200mA, 20A
The AC Current ranges are: 2mA, 200mA and 20A
To measure current, do the following:
1.Turn off power to the circuit. Discharge all high-
voltage capacitors.
2. Insert the red test lead into the A or μAmA (UT58A)
or mA (UT58B/UT58C) terminal and the black test
lead into the COM terminal.
3.Set the rotary switch to an appropriate measurement
position in A or 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.
(See Figure 5)
black red
(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.
The resistance ranges are:
Model UT 58A/UT58B:200Ω,2kΩ ,20kΩ,2M Ω,20MΩ and
200MΩ.
Model UT 58C:200Ω, 2kΩ, 20kΩ, 2MΩ and 20MΩ.
1. Insert the red test lead into the Hz VΩ (UT58C) or
VΩ (UT58A/UT58B) terminal and the black test
lead into the COM terminal.
2. Set the rotary switch to an appropriate measurement
position in Ω range.
3. Connect the test leads across with the object being
measured.
The measured value shows on the display.
Note
The test leads can add 0.1to 0.2Ω of error to the slow-
resistance measurement. To obtain accurate readings
in low-resistance, 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:
measured resistance value (Y) – (X)=accurate readings
of resistance.
If the input terminal short-circuit reading 0.5,check
the test leads for any looseness or other cause.
For high resistance (>1MΩ), it is normal taking several
seconds to obtain a stable reading; select short test
leads for stable and precise readings.
When the resistance is higher than the maximum range
or in open circuit condition, the Meter displays "1".
When resistance measurement has been completed,
disconnect the connection between the testing leads
and the circuit under test.
(See Figure 6)
black red
(Figure 6)
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.
To avoid harms to you, please do not attempt to input
voltages higher than 60V DC or 30V rms 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
To test out a diode out of a circuit, connect the Meter as
follows:
1. Insert the red test lead into the Hz VΩ (UT58C) or
VΩ (UT58A/UT58B) 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