KJ KJ70A User manual

KJ70A/KJ70B
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.
Digital Multimeter Model KJ9801/9802 (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, AC/DC Current,
Resistance, Capacitance, Temperature(only KJ9802), Diodes,
Continuity, hFE of transistor and so on. They are both ideal tool
for users.
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
zTestLead 1pair
zTemperature Probe 1 piece (KJ9802 only)
zConverter Socket 1 piece

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z9V Battery (6F22 or equivalent) 1 pieces
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
Double Insulated. Grounding.
Low battery indicator Diode.
DC(Direct Current).
Continuity Test.
AC (Alternating
Current).
Warning. Refer to the Operating Manual.
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
Figure 1
1
2
4
3
5

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Function description
Rotary
switch
position
Description
DC voltage measurement
V～AC voltage measurement
F Capacitance measurement
ΩResistance measurement
Diode test
Continuity test
DC current measurement
A～AC current measurement
℃Temperature measurement（KJ9802 only）
hFE βvalue measurement of transistor
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 or V～ 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
eletric shock, do not attempt to measure voltages
higher than 1000V 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/AC current Measurement
To measure DC/AC current, connect the Meter as follows:
·Set the rotary switch to desired or A～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. AC current reading is effective
value of sine wave (mean value response).
·Press HOLD button if need.
Warning
a) If magnitude of the current is unknown, always
start with the highest range and reduce until satisfactory

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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) The protection of mA input terminal : Self-Healing Fuse,
and 20A range unfused.
d) When the measured current is more than 10A, the
continuous measurement time is 10 seconds maximum
and interval time between 2 measurements greater than
15 minutes.
e) Remember to cut off the power supply of the circuit be
measured before connect it.
f) Do not apply any voltage to the input when the Meter is
working in current measuring mode.
g) 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

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all the high-voltage capacitors before measuring
resistance.
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

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steady reading when you do the resistance
measurement greater than 1MΩ.
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

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show “1”.
c) In a circuit, a good diode should still produce a forward
voltage drop reading of 0.5V to 0.8; 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.

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·Press HOLD button if need.
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.
Capacitance 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 doing the
measurement.
To measure capacitance, connect the Meter as follows:
·Set the rotary switch to desired F range.
·Connect the Converter Socket into “mA” input terminal and
“COM” input terminal.
·Insert the capacitor’s leg into relevant socket of the
Converter Sockek.
·Read the value from display.
·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 capacitance measuring mode.
b) If capacitance of the circuit or capacitor be measured is
short or higher than the range be selected the display
will show “1”.
c) It is normal for taking a little more time to get the
steady reading when you do the capacitance
measurement greater than 10uF.
d)
When the measurement has been completed,
disconnect the Converter Socket.
e) If you use the test leads to measure directly, 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(KJ9802 only)
To measure temperature, connect the Meter as follows:
·Set the rotary switch to °C range and the display is ambient
temperature.
·Connect the Converter Socket into “mA” input terminal and
“COM” input terminal.
·Connect the leads of temperature probe (k type) into
relevant socket of the Converter Sockek.
·Put the sensor end of the temperature probe into the area

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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
18-23℃and the influence is much greater at low
temperature measuring range.
c) When the measurement has been completed, remove
the temperature probe and disconnect the Converter
Socket.
hFE Measurement
To measure βvalue of transistor, connect the Meter as
follows:
·Set the rotary switch to hFE range.
·Connect the Converter Socket into “mA” input terminal and
“COM” input terminal.
·Connect the legs of transistor be tested into relevant socket
of the Converter Sockek.
·Read the βvalue ( it is approximate value) from display.
·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 hFE measuring mode.
b) When the measurement has been completed,
disconnect the Converter Socket.
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 Power OFF
· If no any operation in 15 minutes, the Meter 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
· Polarity: Auto Polarity
· Overloading: Display “1” or “–1”
· Low battery indicator: display

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· 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) : 170mm x 84mm x 41mm
·Weight: Approx. 300g (protection holster and 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℃
DC Voltage

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Range Resolution Accuracy
200mV 0.1mV
2V 1mV
20V 10mV
200V 100mV
±(0.5%+1)
1000V 1V ±(0.8%+2)
Input impedance：10MΩapprox.
Overload protection:：1000V rms (except 200mV range, it is
250V rms)
AC Voltage
Range Resolution Accuracy
2V 1mV
20V 10mV
200V 100mV
±(0.8%+3)
750V 1V ±(1.2%+3)
Input impedance：10MΩapprox.
Overload protection:：1000V rms
Frequency response ：40Hz ～400Hz （not specified for
≥400Hz）
Display：effective value of sine wave (mean value response)
DC Current

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Range Resolution Accuracy
20μA 0.01μA
2mA 1μA
20mA 10μA
±(0.8%+1)
200mA 0.1mA ±(1.5%+1)
20A 10mA ±(2%+5)
Overload protection：
μA mA range：Self-healing fuse(0.29A/250V)
20A range unfused
Drop voltage：200mV for full scale approx.
Warning
When the measured current is more than 10A, the
continuous measurement time is 10 seconds maximum
and interval time between 2 measurements greater than
15 minutes.
AC Current
Range Resolution Accuracy
2mA 1μA
20mA 10μA ±(1.0%+3)
200mA 0.1mA ±(1.8%+3)
20A 10mA ±(3.0%+5)
Frequency response：40Hz～400Hz
μA mA range：Self-healing fuse(0.29A/250V)
20A range unfused
Drop voltage：200mV for full scale approx.
Display：effective value of sine wave (mean value response)

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Warning
When the measured current is more than 10A, the
continuous measurement time is 10 seconds maximum
and interval time between 2 measurements greater than
15 minutes.
Resistance
Range Resolution Accuracy
200Ω0.1Ω
2KΩ1Ω
20KΩ10Ω
200KΩ100Ω
2MΩ1KΩ
±(0.8%+1)
20MΩ10KΩ±(1.0%+2)
Overload protection：250Vrms
Note:
At 200Ωrange, 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.
Diode test
Range Resolution Description
1mV
Open voltage is 3V approx.
The normal forward voltage of
PN junction is 500 ～800mV
approx.
Overload protection: 250Vrms