Model UT90D: OPERATING MANUAL
1
TABLE OF CONTENTS
TITLE
PAGE
Model UT90D: OPERATING MANUAL
2
Introduction
Dear customer,
thank you for making the excellent decision to purchase this UNI-T product.
You have acquired an above-average quality product from a brand family which has distinguished itself in the field of
measuring, charging and network technology by particular competence and permanent innovation.
The products of the UNI-T family offer optimum solutions even for the most demanding applications for ambitious
hobby electricians as well as for professional users. UNI-T offers you reliable technology at an extraordinarily
favourable cost-performance ratio.
Therefore, we are absolutely sure: Your decision for a UNI-T product is the beginning of a long and successful
cooperation.
And now enjoy your new UNI-T product!
Introduction..................................................................................................................................................................1
Intended use .............................................................................................................................................................. 4
Operating elements ....................................................................................................................................................5
Safety instructions ......................................................................................................................................................6
Product description......................................................................................................................................................9
Scope of delivery ........................................................................................................................................................10
Display Indications and Symbols ................................................................................................................................11
Measuring mode..........................................................................................................................................................12
a) Voltage measuring „V“ ......................................................................................................................................13
b) Current measuring „A“...................................................................................................................................... 14
c) Frequency measuring........................................................................................................................................16
d) Resistance measurement..................................................................................................................................17
e) Diode test ..........................................................................................................................................................18
f) Continuity check................................................................................................................................................19
g) Capacity measuring ..........................................................................................................................................20
REL
∆
function ........................................................................................................................................................21
Low Imp. 400 k
Ω
function ......................................................................................................................................21
Auto power OFF function........................................................................................................................................21
Maintenance and cleaning ........................................................................................................................................ 22
General ..................................................................................................................................................................22
Cleaning..................................................................................................................................................................22
Changing the 10 A fuse ..........................................................................................................................................23
Inserting/changing the battery ................................................................................................................................24
Disposal of flat batteries ........................................................................................................................................25
Disposal...................................................................................................................................................................... 26
Troubleshooting ..........................................................................................................................................................26
Technical data ............................................................................................................................................................ 28
Model UT90D: OPERATING MANUAL
3
TABLE OF CONTENTS
TITLE
PAGE
Model UT90D: OPERATING MANUAL
4
Model UT90D: OPERATING MANUAL
5
Model UT90D: OPERATING MANUAL
6
Intended Use
- Measuring and displaying electric parameters in the range of excess voltage category III (up to max. 600V against
ground potential, pursuant to EN 61010-1) and all lower categories.
- Measuring direct current up to max. 1000 V (CAT II)
- Measuring alternating current up to max. 750 V (CAT II)
- Measurement of direct and alternating current up to 10 A
- Frequency measuring up to 10 MHz
- Capacity measuring up to 100 µF
- Measurement of resistance values of up to 40MOhm
- Continuity check (< 70 Ohm acoustic)
- Diode test
The two current measuring inputs are secured against overload. The voltage in the measuring circuit may not exceed
250 V. The 10 A measuring range is equipped with a fine fuse, the 400 mA measuring range with a self-resetting PTC
fuse.
The device may only be operated with the specified batteries.
The measuring instrument must not be operated when it is open, i.e. with an open battery compartment or when the
battery compartment cover is missing. Measuring in damp rooms or under unfavourable ambient conditions is not
admissible.
For safety reasons, when measuring only use measuring cables or accessories which are adjusted to the specifica-
tions of the multimeter.
Unfavourable ambient conditions are:
- Wetness or high air humidity
- Dust and flammable gases, vapours or solvents
- thunderstorms or similar conditions such as strong electrostatic fields etc.
Any use other than the one described above damages the product. Moreover, this involves dangers such as e.g. short
circuit, fire, electric shock, etc. No part of the product must be modified or rebuilt!
The safety instructions must be followed unconditionally!
Operating elements
1 Detachable rubber holster
2 LC display with connection information
3 REL button for relative measuring function
4 Rotary switch
5 mAµAHz measuring socket (with self-resetting fuse)
6 10 A measuring socket (with fine-wire fuse)
7 V
Ω
capacity measuring socket (with commensurability „+“)
8 COM measuring socket (reference potential)
9 SELECT button for function switching
10 Low imp. 400 k
Ω
button for short-time reduction of the measuring impedance from 10 MOhm to 400 kOhm
Safety instructions
Please read the entire operating instructions before using the product for the first time; they
contain important information on the correct operation.
The guarantee is rendered invalid when damage is incurred as a result of non-compliance with
the operating instructions! We do not assume any liability for any damage arising as a conse-
quence!
We will also not assume any responsibility for damage to assets or for personal injury caused
by improper handling or failure to observe the safety instructions! The warranty is voided in
these cases.
This device left the manufacture’s factory in a safe and perfect condition.
We kindly request the user to observe the safety instructions and warnings contained in this operating manual to pre-
serve this condition and to ensure safe operation!
Please observe the following symbols:
A triangle containing an exclamation mark indicates important information in these operating instruc-
tions which is to be observed without fail.
The triangle containing a lightning symbol warns of danger of an electric shock or of the impairment of
the electrical safety of the device.
The “hand” symbol indicates special information and advice on operation of the device.
Model UT90D: OPERATING MANUAL
7
Model UT90D: OPERATING MANUAL
8
This product has been CE-tested and meets the necessary European guidelines.
Class 2 insulation (double or reinforced insulation)
CAT II
Overvoltage category II for measurements on electric and electronic devices connected to the mains
supply with a power plug. This category also covers all smaller categories (e.g. CAT I for measuring
signal and control voltages).
CAT III
Overvoltage category III for measuring in building installation (e.g. outlets or sub-distribution). This cat-
egory also covers all smaller categories (e.g. CAT II for measuring electronic devices).
Ground potential
The unauthorised conversion and/or modification of the unit is inadmissible because of safety and approval reasons
(CE).
Consult an expert when in doubt about the operation, the safety or the connection of the device.
Measuring instruments and accessories are not toys and have no place in the hands of children.
On industrial sites the accident prevention regulations of the association of the industrial workers’ society for electrical
equipment and utilities must be followed.
Model UT90D: OPERATING MANUAL
9
Model UT90D: OPERATING MANUAL
10
Model UT90D: OPERATING MANUAL
11
Model UT90D: OPERATING MANUAL
12
In schools, training centres, computer and self-help workshops, handling of measuring instruments must be super-
vised by trained personnel in a responsible manner.
Before measuring voltages, always make sure that the measuring instrument is not set to a measuring range for cur-
rents.
The voltage between the connection points of the measuring device and the ground potential must not exceed 600 V
DC/AC in overvoltage category III or 1000 V DC/AC in overvoltage category II.
The test prods have to be removed from the measured object every time the measuring range is changed.
Be especially careful when dealing with voltages higher than 25V AC or 35 V DC. Even at such voltages you can
receive a life-threatening electric shock when you come into contact with electric wires.
Check the measuring device and its measuring lines for damage before each measurement. Never carry out any
measurements if the protecting insulation is defective (torn, ripped off etc.)
To avoid an electric shock, make sure not to touch the connections/measuring points to be measured neither directly
nor indirectly during measurement. During measuring, do not grip beyond the tangible grip range markings present on
the test prods.
Do not use the multimeter just before, during or just after an electrical storm (electrical shock / high-energy overvolt-
ages!). Please make sure that your hands, your shoes, your clothing, the floor, switches and switching components
are dry.
Avoid an operation near:
- strong magnetic or electromagnetic fields
- transmitting aerials or HF generators.
since this could affect the measurement.
If you have a reason to believe that the device can no longer be operated safely, disconnect it immediately and secure
it against being operated unintentionally. It can be assumed that safe operation is no longer possible if:
- the device exhibits visible damage,
- the device does not operate any longer and
- the device was stored under unfavourable conditions for a long period of time or
- the device was exposed to extraordinary stress in transit.
Do not switch the measuring instrument on immediately after it has been taken from a cold to a warm environment.
Condensation water that forms might destroy your device. Leave the device switched off and wait until it has reached
room temperature.
Do not leave the packaging material lying around carelessly since such materials can become dangerous toys in the
hands of children.
You should also heed the safety instructions in each chapter of these instructions.
Product Description
The multimeter (referred to as DMM in the following) indicates measured values on the digital display. The measuring
value display of the DMM comprises 4000 counts (count = smallest display value).
The measuring device can be used for do-it-yourself or for professional applications.
For better readability, the DMM can also be mounted with the clip on the rear.
The mA current section shows an absolute novelty. With this measuring device, it is no longer necessary to replace an
accidentally triggered mA fuse. The installed PTC fuse resets automatically after tripping.
Rotary switch (4)
The individual measuring functions are selected using a rotary switch for which
„auto range“, the automatic range selection, is active. The appropriate range of
measurement is set for each application individually.
With the button „SELECT“ (9), you switch to a sub-function if the measuring func-
tion is double assigned (e.g. switching resistance measuring - diode test and con-
tinuity test or AC/DC switching in the current range).
If the rotary switch is set to „OFF“, the measuring device is switched off. Always
turn the measuring device off when it is not in use.
Prior to working with the measuring device, you first have to insert the enclosed batteries.
Insert the battery as described in the chapter „Cleaning and Maintenance“. A 9V block battery is required for voltage
supply. These are supplied with the device.
Contents
Multimeter with removable rubber holster
9V block battery
Safety measuring cable
Operating instructions
Display indications and symbols
∆
Delta symbol for relative value measuring (= reference value measuring)
Auto range
stands for „automatic measuring range selection“
Connect terminal Graphic notice to select the required measuring sockets
OL
Overload, the measuring range was exceeded
Battery replacement symbol; please replace the batteries immediately to avoid measuring errors!
Symbol for the diode test
Symbol for the acoustic continuity tester
AC
Alternating size for voltage and current
DC
Direct magnitude for voltage and current
mV
millivolt (exp.-3)
V
Volt (unit of electric potential)
A
ampere (unit of electric current)
mA
Milliampere (exp.-3)
µA
Microampere (exp.-6)
Hz
Hertz (unit of frequency)
kHz
Kilohertz (exp.3)
MHz
Megahertz (exp.6)
Ω
Ohm (unit of electric resistance)
k
Ω
Kiloohm (exp.3)
M
Ω
Megaohm (exp.6)
nF
Nanofarad (unit of electric capacity, exp.-9, symbol
)
µF
Microfarad (exp.-6)
Model UT90D: OPERATING MANUAL
13
Model UT90D: OPERATING MANUAL
14
Measuring
Do not exceed the maximum permitted input values. Do not contact circuits or parts of cir-
cuits if there could be voltages higher than 25 V ACrms or 35 V DC present within them. Mor-
tal danger!
Before measuring, check the connected measuring lines for damage such as, for example,
cuts, cracks or squeezing. Defective measuring cables must no longer be used. Mortal danger!
During measuring, do not grip beyond the tangible grip range markings present on the test
prods.
You may only connect the two measuring leads to the measuring device that are required for
measuring operation. Remove all measuring leads not required from the device for safety
reasons.
The display shows the corresponding connection sequence of the measuring sockets for each mea-
suring function. Observe this when connecting the measuring leads to the measuring device.
As soon as „OL“ (overload) appears on the display, you have exceeded the measuring range.
a) Voltage measuring „V“
Proceed as follows to measure DC voltages „DC“ (V
):
- Turn the DMM on at the rotary switch and select measuring range „V
“. For lower voltages up to max. 400 mV,
select the measuring range „mV
“
- Plug the red measuring lead into the V measuring socket and the black mea-
suring lead into the COM measuring socket.
- Now connect the two test prods to the object to be measured (battery, circuit
etc.).
-
The red measuring tip indicates the positive pole, the black measuring tip the
negative pole.
- The polarity of the respective measuring value is indicated on the together
with the current measuring value.
As soon as a minus „-“ appears for direct voltage in front of the
measured value, the measured voltage is negative (or the
measuring leads have been mixed up).
The voltage range „V DC/AC“ shows an input resistance of >10
MOhm, the „mV DC“ measuring range >4000 MOhm.
- After measuring, remove the measuring leads from the measuring object and turn the DMM off. Turn the rotary
switch to „OFF“.
Proceed as follows to measure AC voltages (V
):
- Turn the DMM on at the rotary switch and select measuring range „V
“.
- Plug the red measuring lead into the V measuring socket and the black measuring lead into the COM measuring
socket.
- Now connect the two measuring prods to the object to be measured (generator, switching etc.).
- The measuring value is indicated on the display
- After measuring, remove the measuring leads from the measuring object and turn the DMM off. Turn the rotary
switch to „OFF“.
Model UT90D: OPERATING MANUAL
15
Model UT90D: OPERATING MANUAL
16
Model UT90D: OPERATING MANUAL
17
Model UT90D: OPERATING MANUAL
18
Model UT90D: OPERATING MANUAL
19
Model UT90D: OPERATING MANUAL
20
b) Current measuring „A“
Do not exceed the maximum permitted input values. Do not contact circuits or parts of cir-
cuits if there could be voltages higher than 25 V ACrms or 35 V DC present within them. Mor-
tal danger!
The voltage in the measuring circuit may not exceed 250 V.
Measuring in the 10 A range may only be performed for max. 10 seconds and at 15 minute
intervals.
Current measuring operations are possible in three ranges. The first range is from 0 to 4000µA, the second from 0 to
400mA and the third from 0 to 10 A. All current measuring ranges are protected against overload.
The mA measuring input has a self-resetting PTC fuse; fuse changes are not required.
If the mA fuse tripped (measured value does not change etc.), turn the DMM off (OFF) and wait
about five minutes. The self-resetting fuse cools down and then functions again.
Proceed as follows to measure DC voltages:
- If you want to measure currents of up to max. 4000µA, set the rotary switch to
position „µA“ or to position „mA“ respectively up to max. 400 mA or to position
„A“ for max. 10 A. The display shows „DC“.
- Plug the red measuring lead into the 10 A measuring socket (with currents > 400
mA) or into the mAµA measuring socket (with currents <400 mA). Plug the black
measuring lead into the COM socket.
- Now connect the two test prods in series with the object to be measured (battery,
circuit etc.); the display indicates the polarity of the measured value together with
the currently measured value.
As soon as a minus „-“ appears for the direct voltage measuring in
front of the measuring value, the measured voltage is negative (or
the measuring tips have been mixed up).
After measuring, remove the measuring leads from the measuring object and turn
the DMM off. Turn the rotary switch to „OFF“.
Proceed as described above to measure alternating currents.
Press „SELECT“ (9) to switch to the AC range. „AC“ appears on the display.
Pressing this button again, takes you back etc.
After measuring, remove the measuring leads from the measuring object and turn the DMM off. Turn the rotary switch
to „OFF“.
Do not measure any currents above 10 A in the 10A range and no currents above 400 mA in the
mA/µA range, otherwise the fuses trigger.
c) Frequency measurement
The DMM can be used to measure and indicate signal voltage frequencies up to
10 MHz.
Proceed as follows to measure frequencies:
- Turn the DMM on at the rotary switch and select measuring range „Hz“. The dis-
play reads „Hz“.
- Plug the red measuring lead into the Hz measuring socket and the black mea-
suring lead into the COM measuring socket.
- Now connect the two test prods with the object to be measured (signal generator,
circuit etc.).
- The frequency and corresponding unit are displayed.
- After measuring, remove the measuring leads from the measuring object and
turn the DMM off. Turn the rotary switch to „OFF“.
d) Resistance measuring
Make sure that all the circuit parts, switches and components and other objects of measure-
ment are disconnected from the voltage at all times.
Proceed as follows to measure the resistance:
- Turn the DMM on at the rotary switch and select measuring range „
Ω
“.
- Plug the red measuring lead into the
Ω
measuring socket and the black measur-
ing lead into the COM measuring socket.
- Check the measuring leads for continuity by connecting both measuring prods to
one another. After that the resistance value must be approximately 0.5 Ohm
(inherent resistance of the measuring leads).
- Press the button „REL“ (3) to not let the inherent resistance of the measuring
leads flow into the following resistance measuring. The display shows 0 Ohm
- Now connect the measuring prods to the object to be measured. As long as the
object to be measured is not high-resistive or interrupted, the measured value
will be indicated on the display. Wait until the display has stabilised. With resis-
tances of >1 MOhm, this may take a few seconds.
- As soon as „OL“ (overload) appears on the display, you have exceeded the mea-
suring range or the measuring circuit has been broken.
- After measuring, remove the measuring leads from the measuring object and turn the DMM off. Turn the rotary
switch to „OFF“.
If you carry out a resistance measurement, make sure that the measuring points which you contact
with the measuring prods are free from dirt, oil, solderable lacquer or similar. An incorrect
measurement may result under such circumstances.
e) Diode test
Make sure that all the circuit parts, switches and components and other objects of measure-
ment are disconnected from the voltage at all times.
- Turn the DMM on at the rotary switch and select measuring range „
“.
- Plug the red measuring lead into the
Ω
measuring socket and the black measur-
ing lead into the COM measuring socket.
- To activate the function „Diode test“, press the button „SELECT“ (9). Pressing this
button again takes you to the next measuring function (continuity check) etc.
- The display indicates the diode symbol
.
- Check the measuring leads for continuity by connecting both measuring prods to
one another. After that the value must be approximately 0 V.
- Now connect the two measuring prods with the object to be measured (diode).
- The display shows the continuity voltage in volt (V). If „OL“ is indicated, the diode
is measured in reverse direction or the diode is faulty (interruption). Perform a
counter-pole measuring for control reasons.
- After measuring, remove the measuring leads from the measuring object and
turn the DMM off. Turn the rotary switch to „OFF“.
f) Continuity check
Make sure that all the circuit parts, switches and components and other objects of measure-
ment are disconnected from the voltage and discharged.
- Turn the DMM on at the rotary switch and select measuring range
- Plug the red measuring lead into the
Ω
measuring socket and the black measur-
ing lead into the COM measuring socket.
- To activate the acoustic continuity test function, press the button „SELECT“ (9).
Pressing this button again takes you back to the first measuring function (resis-
tance measuring) etc.
- The display indicates the symbol „Continuity test“
.
- A measuring value of less than 70 Ohm is identified as continuity; in this case a
beep sounds. A permanent beep sounds as of <10 Ohm.
- As soon as „OL“ (overload) appears on the display, you have exceeded the mea-
suring range or the measuring circuit has been broken.
- After measuring, remove the measuring leads from the measuring object and
turn the DMM off. Turn the rotary switch to „OFF“.
Model UT90D: OPERATING MANUAL
21
Model UT90D: OPERATING MANUAL
22
Model UT90D: OPERATING MANUAL
23
Model UT90D: OPERATING MANUAL
24
Model UT90D: OPERATING MANUAL
25
Model UT90D: OPERATING MANUAL
26
Model UT90D: OPERATING MANUAL
27
Model UT90D: OPERATING MANUAL
28
g) Capacity measuring
Make sure that all the circuit parts, switches and components and other objects of measure-
ment are disconnected from the voltage and discharged.
With electrolyte capacitors, observe the polarity.
- Turn the DMM on at the rotary switch and select measuring range
- Plug the red measuring lead into the V measuring socket and the black measur-
ing lead into the COM measuring socket.
- The display shows the unit „nF“.
Due to the sensitive measuring input, the display may show a value
in case of „open“ measuring leads. By pressing the button „REL
∆
“,
the display is set to „0“.
- Now connect the two test prods (red = positive pole/black = negative pole) with
the object to be measured (condenser). After a short while the display shows the
capacity. Wait until the display has stabilised. With capacities of >40 µF, this may
take a few seconds.
- As soon as „OL“ (overload) appears on the display, you have exceeded the mea-
suring range.
- After measuring, remove the measuring leads from the measuring object and
turn the DMM off. Turn the rotary switch to „OFF“.
REL
∆
function
The REL function allows a reference value measurement to avoid possible line losses which may caused e.g. during
resistance measurements. For this purpose, the current indicated value is set to zero. A new reference value is set.
Press the „REL
∆
“ button to activate this measuring function. The display shows „
∆
“. The automatic measuring range
selection is deactivated now.
To turn this function off, keep the button „REL
∆
“ depressed until „
∆
“ goes off.
Low Imp. 400 k
Ω
function
This function may only be used for voltages of a max. of 250 V and a max. of 3 seconds!
This measuring function enables the reduction of the measuring impedance from 10 MW to 400 kW. Through the
reduction of the measuring impedance, possible phantom voltages are suppressed, which could falsify the mea-
suring result.
Press this button during voltage measurement (max. 250 V) for a max. of 3 seconds. After release, the multimeter has
the normal measuring impedance of 10 M
Ω
.
Auto power OFF function
The DMM turns off automatically after 30 minutes if no button or switch is operated. This function saves battery pow-
er and extends the service life.
To reactivate the DMM after automatic shutdown, use the rotary switch or press the „REL“ or „SELECT“ button.
You can turn the auto power-off function manually.
To do so, turn the measuring device off (OFF). Keep the button „SELECT“ depressed and turn the DMM on at the
rotary switch. This function remains inactive until the measuring device is turned off via the rotary switch.
Maintenance and cleaning
General information
To ensure the accuracy of the multimeter over an extended period of time, it should be calibrated once a year.
Apart from occasional cleaning and fuse replacements, the multimeter requires no servicing.
Information on changing the battery and fuse appears below.
Regularly check the technical safety of the instrument and measuring lines, e.g. check for dam-
age to the housing or squeezing etc.
Cleaning
Always observe the following safety instructions before cleaning the device:
Live components may be exposed if covers are opened or parts are removed (unless this can
be done without tools).
The connected lines must be disconnected from the measuring device and all measuring
objects prior to cleaning or repairing the device. Switch the DMM off.
Do not use any carbon-containing cleaning agents or petrol, alcohol or the like to clean the product. These could cor-
rode the surface of the measuring instrument. The fumes are furthermore a health hazard and are explosive. More-
over, you should not use sharp-edged tools, screwdrivers or metal brushes or similar for cleaning.
For cleaning the device or the display and the measuring lines, use a clean, fuzz-free, antistatic slightly damp cloth.
Changing the 10 A fuse
The 10 A measuring range is protected against overload with a standard fine-wire fuse. If measuring in this range is
no longer possible, you have to change the fuse.
Proceed as follows for replacement
- Separate the connected measuring leads from the measuring circuit and the measuring device. Switch the DMM off.
- Slide the rubber holster off the device.
- Unscrew the three screws on the back of the device and carefully pull the casing apart.
- Replace the defective fuse with a new fuse of the same type and nominal voltage. The fuse has the following values:
Fine-wire fuse, quick-action, 10A / 250 V (5 x 20 mm) Common name F10A250V.
- Now close the casing carefully. Replace the rubber holster on the device.
Using mended fuses or bridging the fuse holder is not admissible for safety reasons.
Never operate the measurement device when it is open. !RISK OF FATAL INJURY!
Inserting/changing the batteries
Operation of the measuring device requires a 9V battery (1604A). You need to insert a new, charged battery prior to
initial operation or when the battery change symbol
appears on the display.
To insert/replace the battery, proceed as follows:
- Separate the connected measuring leads from the measuring circuit and the measuring device. Switch the DMM off.
- Slide the rubber holster off the device.
- Unscrew the three screws on the back of the device and carefully pull the casing apart.
- Connect a new battery with the battery clip in the DMM observing the right polarity.
- Now close the casing carefully.
Never operate the measuring instrument when it is open. !RISK OF FATAL INJURY!
Do not leave flat batteries in the appliance. Even batteries protected against leaking can cor-
rode and thus release chemicals which may be detrimental to your health or damage the appli-
ance.
Do not leave batteries lying around carelessly. They might be swallowed by children or pets. If
swallowed, consult a doctor immediately.
Remove the batteries if the device is not used for longer periods of time to prevent leaking.
Leaking or damaged batteries may cause alkali burns if they come in contact with the skin.
Therefore, use suitable protective gloves.
Make sure that the batteries are not short-circuited. Do not throw batteries into fire!
Batteries may not be recharged. There could be danger of explosion.
You can order suitable alkaline batteries stating the following order no.:
Order no.: 65 25 09 (please order 1).
Only use alkaline batteries, since these are powerful and have a long life.
Disposal of flat batteries
You, as the end customer, are legally obliged (Battery Ordinance) to return all used batteries and accumulators.
Disposal in the household waste is prohibited!
Contaminated batteries/rechargeable batteries are labelled with these symbols to indicate that disposal
in domestic waste is forbidden. The description of dangerous heavy metal constituents are: Cd =
Cadmium, Hg = Mercury, Pb = Lead. Vous pouvez rapporter gratuitement vos piles et accumulateurs
usagés aux centres de récupération de votre commune, à nos succursales ou à tous les points de vente
de piles et d’accumulateurs !
You thereby meet the legal obligations and contribute to the protection of the environment!
Disposal
Old electronic devices are hazardous waste and should not be disposed of in the household waste.
When the device has become unusable, dispose of it in accordance with the current statutory
regulations at the communal collection points. It is forbidden to dispose of it in the household waste.
Troubleshooting
In purchasing the DMM, you have acquired a product which has been designed to the state of the art and is
operationally reliable.
Nevertheless, problems or faults may occur.
For this reason, the following is a description of how you can eliminate possible malfunctions yourself.
Please always observe the safety instructions!
Error
Possible cause
Remedy
The multimeter
Is the battery dead?
Check the status.
does not work.
None measuring
Is the wrong measuring function active
Check the display (AC/DC)
value change.
(AC/DC)?
and switch the function if applicable.
Did you use the wrong measuring sockets?
Compare the connection with the
display.
Is the fuse defect?
In mA/µA range: Turn the measuring
device off and wait approx. 5 minutes
until the PTC fuse is reset automatically.
In the 10 A range: Change the fuse as
described in the chapter „Changing the
fuse“.
Repairs other than those described should only be carried out by an authorised specialist.
If you have queries about handling the measuring device, our technical support is available under the
following telephone number:
Model UT90D: OPERATING MANUAL
29
Model UT90D: OPERATING MANUAL
30
Model UT90D: OPERATING MANUAL
31
Model UT90D: OPERATING MANUAL
32
Technical data
Display
4000 counts
Measuring frequency
approx. 2-3 measuring operations/second
Measuring lead length
about 75 cm each
Measuring impedance
>10M
Ω
(V range)
Operating voltage
9-V compound battery
Working temperature
0°C to 40°C
Operating height
max. 2,000 m
Storage temperature
-10°C to +50°C
Weight
ca. 340 g
Dimensions (LxWxH)
177 x 85 x 40 (mm)
Over-voltage category
CAT III 600 V (incl. CAT II 1000 V)
Measurement tolerances
Statement of accuracy in ± (% of r display error in counts (= number of smallest points)). The accuracy is
valid for one year at a temperature of +23°C ± 5°C, and at a relative humidity of less than 75 %, non-condensing.
Direct voltage, overload protection 1000 V
Range
Accuracy
Resolution
400 mV
±(0,8% + 3)
0.1 mV
4 V
1 mV
40 V
±(0,8% + 1)
10 mV
400 V
100 mV
1000 V
±(1% + 3)
1 V
Alternating voltage, overload protection 750 V
Range (40-400 Hz)
Accuracy
Resolution
4 V
±(1,2% + 5)
1 mV
40 V
±(1% + 5)
10 mV
400 V
100 mV
600 V
±(1,2% + 5)
1 V
Direct current, overload protection 400 mA/250V + 10 A/250 V
Range
Accuracy
Resolution
400 µA
±(1% + 2)
0,1 µA
4,000 µA
1 µA
40 mA
±(1.2% + 3)
10 µA
400 mA
100 µA
4 A
±(1.5% + 5)
1 mA
10 A
10 mA
Alternating current, overload protection 400mA/250V + 10 A/250 V
Range (40-400 Hz)
Accuracy
Resolution
400 µA
±(1.5% + 5)
0,1 µA
4000 µA
1 µA
40 mA
±(2% + 5)
10 µA
400mA
100 µA
4 A
±(2.5% + 5)
1 mA
10 A
10 mA
Resistance, overload protection 1000V/DC or 750V/AC
Range
Accuracy
Resolution
400
Ω
±(1,2% + 2)
0,1
Ω
4 K
Ω
1
Ω
40 K
Ω
±(1% + 2)
10
Ω
400 K
Ω
100
Ω
4 M
Ω
±(1,2% + 2)
1 k
Ω
40 M
Ω
±(1.5% + 2)
10 K
Ω
Capacity, overload protection 1000V/DC or 750V/AC
Range
Accuracy
Resolution
40 nF
±(3% + 10)
0.01 nF
400 nF
0.1 nF
4 µF
±(3% + 5)
1 nF
40 µF
0.01 µF
100 µF
±(4% + 5)
0.1 µF
Frequency, overload protection 250 V
Range
Accuracy
Resolution
10 Hz - 10 MHz
0,01 Hz - 0,01 MHz
max. 30 Vrms
Sensitivity:
±(0,1% + 3)
< 1 MHz = 300 mV
> 1 MHz = 600 mV
Acoustic continuity tester
<70
Ω
(<10
Ω
permanent beep)
Diode test test voltage:
1.48V / test voltage ca.1 mA
Diode overload protection/continuity tester: 1000V/DC or 750V/AC
Do not exceed the maximum permitted input values. Do not touch any circuits or parts of
circuits, if they can have higher voltages than 25 V Acrms or 35 V DC. Mortal danger!
Copyright 2008 Uni-Trend Group Limited.
All rights reserved.
Manufacturer:
Uni-Trend Technology (Dongguan) Limited
Dong Fang Da Dao
Bei Shan Dong Fang Industrial Development District
Hu Men Town, Dongguan City
Guang Dong Province
China
Postal Code: 523 925
Headquarters:
Uni-Trend Group Limited
Rm901, 9/F, Nanyang Plaza
57 Hung To Road
Kwun Tong
Kowloon, Hong Kong
Tel: (852) 2950 9168
Fax: (852) 2950 9303
Email: info@uni-trend.com
http://www.uni-trend.com
