KJ KJ2818 User manual

KJ2818
Automotive Digital Multimeter
Operation Manual

1
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.
KJ2818 Automotive Digital Multimeter (hereafter referred to
as “the Meter”) are 3 1/2 digits with steady operations,
fashionable structure and highly reliable hand-held
measuring instrument. The Meter uses large scale of
integrated circuit with double integrated A/D converter as its
core and has full range overload protection.
The Meter can measure AC/DC Voltage, DC Current,
Resistance, Duty Cyle, Temperature, Diodes, Continuity,
Automobile Ignition Dwell, Engine Tach (Rotation Speed)
and so on.
Unpacking Inspection
Open the package case and take out the Meter. Check the
following items carefully to see any missing or damaged part:
zOperating Manual 1 piece
zTest Lead 1 pair
zTemperature Probe 1 piece (K-type)

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z9V Battery (6F22 or equivalent) 1 piece
In the event you find any missing or damage, please
contact your dealer immediately.
Safety Information
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.
This Meter complies with the standards IEC 61010-1: in
pollution degree 2, overvoltage category (CAT.II
1000V,CAT.III 600V) and double insulation.
CAT.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.
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:
zBefore using the Meter inspect the case. Do not use
the Meter if it is damaged or the case (or part of the

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case) is removed. Look for cracks or missing plastic.
Pay attention to the insulation around the connectors.
zInspect 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.
zDo not apply more than the rated voltage, as marked on
the Meter, between the terminals or between any terminal
and grounding. 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.
zWhen measurement has been completed, disconnect the
connection between the test leads and the circuit under
test, remove the testing leads away from the input
terminals of the Meter and turn the Meter power off.
zThe 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.
zDo not carry out the measurement when the
Meter’s cover is not closed to avoid electric shock.
zDo not input higher than 1000V between the Meter’s
terminals and the grounding to avoid electric shock and
damages to the Meter.
zWhen 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.
zUse the proper terminals, function, and range for your

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measurements.
zDo 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.
zWhen using the test leads, keep your fingers behind the
finger guards.
zDisconnect circuit power and discharge all high-voltage
capacitors before testing resistance, continuity and diode.
zReplace the battery as soon as the low battery indicator
“”appears. With a low battery, the Meter might produce
false readings that can lead to electric shock and personal
injury.
zWhen servicing the Meter, use only the same model
number or identical electrical specifications
replacement parts.
zThe internal circuit of the Meter shall not be altered at will
to avoid damage of the Meter and any accident.
zSoft 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.
zThe Meter is suitable for indoor use.
zTurn the Meter off when it is not in use and take out the
battery when not using for a long time.
zConstantly 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.

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International electrical symbols
Low battery indicator Grounding
～AC (Alternating
Current)
DC(Direct
Current)
Warning. Refer to the
Operating Manual
Double
Insulated
Conforms to Standards of European Union
The Meter Structure(see figure 1)
1. LCD Display
2. Data HOLD button
3. Rotary Switch
4. Input Terminals
5. Power switch
6. Auto Light-on backlight sensor
Figure 1

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Function description
Rotary switch
position Description
DCV DC voltage measurement
ACV AC voltage measurement
OHM Resistance measurement
Diode test
Continuity test
DCA DC current measurement
℃Temperature measurement
FREQ Frequency measurement
TACH Engine Tach (Rotation Speed)
measurement
DWELL Automobile Ignition Dwell measurement
Buttons
POWER Power switch
HOLD Data hold button
Measurement Operation
DC/AC Voltage Measurement
To measure DC/AC voltage, connect the Meter as follows:
·Set the rotary switch to desired DCV or ACV range.
·Connect the RED test lead into “VΩ” input terminal and
BLACK test lead into “COM” input terminal.
·Connect the test leads across with the object being
measured.
·Read the value from display. AC voltage reading is effective
value of sine wave (mean value response).
·Press HOLD button if need.

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Warning
a) To avoid harms to you or damages to the Meter from
electrical shock, do not attempt to measure voltages
higher than DC1000V /AC 750V rms, although readings
may be obtained.
b) 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.
c) When the measurement has been completed,
disconnect the connection between the testing leads and
the circuit under test and remove testing leads from the
input terminals.
DC current Measurement
To measure DC current, connect the Meter as follows:
·Set the rotary switch to desired DCA range.
·Connect the RED test lead into “mA” or “20A” input terminal
and BLACK test lead into “COM” input terminal.
·Connect the test leads in series with the circuit being
measured.
·Read the value from display.
·Press HOLD button if need.
Warning
a) If magnitude of the current is unknown, always

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start with the highest range and reduce until satisfactory
reading is obtained.
b) If “1” or “-1” is shown on the LCD, it means the Meter is
overloaded, then set the measuring range to higher.
c) When the measured current is more than or equal to
10A, the continuous measurement time is 10 seconds
maximum and interval time between 2 measurements
greater than 15 minutes.
d) Remember to cut off the power supply of the circuit be
measured before connect it.
e) Do not apply any voltage to the input when the Meter is
working in current measuring mode.
f) When the measurement has been completed,
disconnect the connection between the testing leads
and the circuit under test and remove testing leads from
the input terminals.
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.

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To measure resistance, connect the Meter as follows:
·Set the rotary switch to desired Ωrange.
·Connect the RED test lead into “VΩ” input terminal and
BLACK test lead into “COM” input terminal.
·Connect the test leads across with the object being
measured.
·Read the value from display.
·Press HOLD button if need.
Warning
a) Do not apply any voltage to the input when the Meter is
working in resistance measuring mode.
b) If resistance of the circuit or resistor be measured is
open or higher than the range be selected the display
will show “1”.
c) For low resistance measurement, it maybe make
some additional error due to the resistance of the test
leads, at this case, as a tip you can short the test leads
firstly and record down the resistance, then subtract it
from the measuring value to obtain the more accurate
result. If the short resistance of the test leads is up to
0.5Ω, it is need to double check if the test leads are
loosened or other troubles exist.
d) It is normal for taking a couple of seconds to get the
steady reading when you do the resistance
measurement greater than 1MΩ.

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e) When the measurement has been completed,
disconnect the connection between the testing leads
and the circuit under test and remove testing leads from
the input terminals.
Diode 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 testing
the diode in circuit.
To do diode test, connect the Meter as follows:
·Set the rotary switch to range.
·Connect the RED test lead into “VΩ” input terminal and
BLACK test lead into “COM” input terminal.
·Connect the RED test lead to the anode and BLACK test
lead to cathode of the diode be tested.
·Read the approx. forward voltage of the diode from the
display. For Si diode this voltage is normal of 500～800mV.
·Press HOLD button if need.
Warning
a) Do not apply any voltage to the input when the Meter is
working in diode test mode.
b) If diode is open or connected by reverse the display will
show “1”.

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c) In a circuit, a good diode should still produce a forward
voltage drop reading of 0.5V to 0.8V, however, the
reverse voltage drop reading can vary depending on the
resistance of other pathways between the probe tips.
d) When the measurement has been completed,
disconnect the connection between the testing leads
and the circuit under test and remove testing leads from
the input terminals.
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 doing
continuity test in circuit.
To do continuity test, connect the Meter as follows:
·Set the rotary switch to range.
·Connect the RED test lead into “VΩ” input terminal and
BLACK test lead into “COM” input terminal.
·Connect the test leads across with the object being tested.
·Read the value from the display.
·The buzzer sounds if the resistance of a circuit under test is
less than or equal to 10Ω. The buzzer may or may not
sounds if the resistance of a circuit under test is between
10Ωto 70Ω. The buzzer does not sound if the resistance of
a circuit under test is higher than 70Ω.
·Press HOLD button if need.

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Warning
a) Do not apply any voltage to the input when the Meter is
working in contonuity test mode.
b) The open voltage of input terminal is approx. 3V.
c) When the measurement has been completed,
disconnect the connection between the testing leads
and the circuit under test and remove testing leads from
the input terminals.
Temperature Measurement
To measure temperature, connect the Meter as follows:
·Set the rotary switch to °C range and the display is ambient
temperature.
·Connect the red lead of temperature probe (k type) into
“mA" input terminal and black lead of it into “VΩ” input
terminal..
·Put the sensor end of the temperature probe into the area
want to measured.
·Read the value from display.
·Press HOLD button if need.
Warning
a) Do not apply any voltage to the input when the Meter is
working in temperature measuring mode.
b) It will result additional error if the Meter is placed out of

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18-23℃and the influence is much greater at low
temperature measuring range.
c) When the measurement has been completed,
disconnect the temperature probe.
Frequency Measurement
To measure frequency, connect the Meter as follows:
·Set the rotary switch to desired 200kHz or 2kHz range.
·Connect the RED test lead into “VΩ” input terminal and
BLACK test lead into “COM” input terminal.
·Connect the test leads across with the object being
measured.
·Read the value from display, the unit is kHz.
·Press HOLD button if need.
Warning
a) Don’t apply the voltage more than 250V RMS to the
meter at the frequency range.
b) When the measurement has been completed,
disconnect the connection between the testing leads
and the circuit under test and remove testing leads from
the input terminals.
Duty Cycle Measurement
To avoid harm to yourselves, never attempt to input
an effective voltage over 60V in DC or 30V in AC.

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To measure duty cycle, connect the Meter as follows:
·Connect the RED test lead into “VΩ” input terminal and
BLACK test lead into “COM” input terminal.
·Set the rotary switch to Duty%.
·Connect the test leads across with the object being
measured.
·The measured value shows on the display, the unit is %.
Warning
a) This measurement method is applicable to input scope
<30Vrms. When the input scope 30Vrms, the input
protection circuit may move which cause cannot get
any reading.
b) When duty cycle testing has been completed,
disconnect the connection between the temperature
probe and the circuit under test.
Engine Tach (Rotation Speed) testing
The RPM means the rotating frequency of the main shaft
of the engine per minute.
To measure Engine Tach, connect the Meter as follows:
·Connect the RED test lead into “VΩ” input terminal and
BLACK test lead into “COM” input terminal.
·Set the rotary switch to desired TACHx10 range according
to an appropriate number of cylinders.
·Connect the RED test lead to the negative end of Ignition
Coil and BLACK test lead to good ground terminal of the

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automobile.
zIf a DIS ignition system without any distributor board
is used in the automobile, connect the red test lead
probe to the TACH (tachometer) signal line (which is
connected to the computer DIS module of the
automotive engine). Refer to the automotive
servicing manual for the specific position.
zIf an ignition system with a distributor board is
used in the automobile, connect the red test
lead probe to the primary negative end of the
ignition coil. (Refer to the automotive servicing
manual for the specific position.)
·Upon the start of the engine or during its operation,
test the rotation speed of the engine and read the
displayed value from the display. The unit is “x10RPM”.
Dwell Testing
It was very important in the past to test the dwell of the
cut-off switch of an ignition system. The dwell testing
means the duration when the cut-off switch remains off
when the cam is turning. Now as an automobile is ignited

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electronically, it is no longer necessary to adjust the
dwell. In addition, the dwell testing can also be used to
test a mixed-controlled solenoid.
(e.g. GM feedback carburetor).
·Set the rotary switch to DWELL .
·Insert the RED test lead “VΩ” input terminal and BLACK
test lead into “COM” input terminal.
·Connect the RED test lead to the negative end of Ignition
Coil and BLACK test lead to good ground terminal of the
automobile.
zIf the cut-off switch of an ignition system is tested,
connect the red test lead probe to the primary negative
end of the ignition coil. (Refer to the automotive
servicing manual for the specific position.)
zIf the GM feedback carburetor is tested, connect the
red probe to the ground terminal or the computer drive
of the solenoid. (Refer to the automotive servicing
manual for the specific position.)
zIf the dwell of an arbitrary ON/OFF equipment is tested,
connect the red probe to the end of the equipment,
fixed with an ON/OFF switch.

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·Read the ignition dwell of the tested automobile directly
from the display.
HOLD button（Data Hold）
· Press HOLD button to enter and exit the Hold mode in any
measuring mode. When it is active, the display value will
be freezed on display until it be released.
Auto Backlight on
When you work at the dark area, the backlight will be
turned on automatically. It help you read value clearly
from the display. The backlight will turned off
automatically when it brought back to bright condition.
Auto Power OFF
When the meter turned on after about 15 minutes it will
enter sleep mode and it has a little power consumption
and the display is blank during it sleep. You can push the
power switch twice to wake it up.
Specifications
General Specifications
· Display: 3 1/2 digits LCD display, Maximum display
1999

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· Polarity: Auto Polarity
· Overloading: Display “1” or “–1”
· Low battery indicator: display
· Sampling rate: 2～3 times/second
· Range mode : Manual range
· Power: 9V Battery (6F22 or equivalent) 1 pieces
·Operating temperature: 0～40℃（32℉～104℉）
·Storage temperature:（-10～50℃）（14℉～122℉）
·Humidity: 0℃～30℃≤75%RH
30℃～40℃≤50%RH
·Dimensions (L x W x D) : 172 mm X 83.5 mm X 48mm
·Weight: Approx. 335g (battery included)
·Safety standards: IEC 61010-1 in pollution degree2,
overvoltage category (CAT.II 1000V,CAT.III 600V) and
double insulation.
·Safety certificate：
·μA/mA input protection: Self-Healing Fuse
·EMC consider: the accuracy is need to add 5% of full
scale as the final accuracy when the strength of RF
field less than1V/m and not specified when it more
than 1V/m.
Accurate Specifications
Accuracy：±（a%reading+b digits），guarantee for 1 year.
Operating temperature: 23℃± 5℃
Relative humidity: ≤75%R.H.
Temperature coefficient: 0.1x(specified accuracy)/1℃

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DC Voltage
Range Resolution Accuracy
200mV 0.1mV
2V 1mV
20V 10mV
200V 100mV
±(0.5%+5)
1000V 1V ±(0.8%+5)
Input impedance：10MΩapprox.
Overload protection:：1000V rms (except 200mV range, it is
250V rms)
AC Voltage
Range Resolution Accuracy
200V 100mV
700V 1V ±(1.2%+5)
Input impedance：4.52MΩapprox.
Overload protection:：1000V rms
Frequency response ：40Hz ～400Hz （not specified for
≥400Hz）
Display：effective value of sine wave (mean value response)