Shenzhen Kejie Instrument Co., Ltd. KJ2815B User manual

KJ2815B/KJ2817B
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 KJ2815B/KJ2817B (hereafter referred
to as “the Meter”) are 3 3/4 digits with steady operations,
fashionable structure and highly reliable hand-held measuring
instrument. The Meter uses large scale of integrated circuit with
high performance A/D converter as its core and has full range
overload protection.
The Meter can measure AC/DC Voltage, AC/DC Current,
Resistance, Capacitance, Diodes, Continuity, Frequency
(KJ2817B only) , Duty cycle (KJ2817B only), Temperature
(KJ2817B only) and so on. Backlight function also provided for
both two model, it is convenient for operating in dark environment.
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

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z2*1.5V AAA Battery 2 pieces
zTemperature probe 1 pieces (KJ2817B only)
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:

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zBefore 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.
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

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should be taken for there is danger of electric
shock.
zUse the proper terminals, function, and range for your
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.

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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.
International electrical symbols
Double Insulated. Grounding.
Low battery indicator Diode.
DC(Direct Current). AC or DC.
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. Function button
3. Rotary Switch
4. VΩCAP（C）Input Terminal
5. COM Terminal
6. μAmA Input Terminal
7. 10A Input Terminals

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Figure 1
Functional Button Description
☼HOLD button (Backlight Coltrol / Data Hold)
As HOLD function, press it to enter and exit the data hold
mode. When it is active, the display value will be freezed on
display until it be pressed again.
As Backlight Control, press and hold this button for over 2
seconds to light on the backlight, until press and hold it for
over 2 seconds again to turn off, or it will keep on always.
When backlight is on the power consumption is increasing, it
will reduce the battery life, so it be recommended not working
at backlight on for long time to save the battery power.

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REL button（KJ2817B only）
The REL mode applies to all measurement functions except
in frequency/duty cycle measurement, it subtracts a stored
value from the present value and displays the relative value
(Δ) as the result.
The definition is as follows:
Relative value (Δ) = present value - stored value
For example, if the stored value is 10.0V and the present
value is 12.0V, the reading would be 2.0V.
If a new measurement value is equal to the stored value then
display 0.0V.
To enter or exit REL mode:
Use rotary switch to select the measurement function before
selecting REL. If measurement functions change manually
after REL is selected, the Meter exits the REL mode.
Press REL to enter REL mode, autoranging turns off except
under capacitance testing mode, and the present
measurement range is locked and display the last
measurement value as "0" as the stored value. Press REL
again or turn the rotary switch to reset the stored value and
exit REL Mode.
Pressing HOLD in REL mode makes the Meter stop updating.
Pressing HOLD again to resume updating.
Hz% button (Frequency/Duty cycle switch, KJ2817B

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only)
At frequency range, the Meter defaults to frequency counter.
Press Hz% to enter duty cycle mode, the Meter beeps, press
Hz% again return to frequency counter function, the Meter
beeps.
At AC voltage or AC current range, press Hz% to start
frequency counter, the Meter beeps. Press Hz% again to
enter duty cycle mode, the Meter beeps, and press it third
time the Meter return to AC voltage or AC current measuring
mode. Then the pressing actions will repeat above turns.
At AC voltage or AC current measuring mode press Hz%, the
autoranging turn off and the Meter stay in the range when
Hz% is pressed. For this case, the sensitivity and measuring
range as below:
Table 1. Sensitivity of frequency measurement
Range Sensitivity
Measuring
Range
4V ≥1.0V 5～10kHz
40V ≥5.0V 5～20kHz
400V ≥45V 45～4kHz
1000/～750V ≥420V 45～1.6kHz
mA ≥45mA 5～5kHz
A ≥4A 45～1kHz
RANGE button(Auto Ranging/Manual Ranging)
The Meter has both manual range and autorange options.

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In the autorange mode, the Meter selects the best range for
the input detected. This allows you to switch test points
without having to reset the range. In the manual range mode,
you select the range. This allows you to override autorange
and lock the Meter in a specific range.The Meter defaults to
the autorange mode in measurement functions that have
more than one range. At the autorange mode, press RANGE
the Meter enters the manual range mode. Each presses of
RANGE increments the range. When the highest range is
reached, the Meter wraps to the lowest range. To exit the
manual range mode, press and hold RANGE for over 2
seconds. The Meter returns to the autorange mode.
Frequency and duty cycle measuring mode only provided
autoranging.
Yellow button (function select)
It uses for selecting the required measurement function when
there is more than one function at one position of the rotary
switch.
POWER button (power switch)
This is a self-lock switch use to turn on or off the power of the
Meter.
Function description

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Rotary switch
position Description
DC voltage measurement
AC voltage measurement
DC millivoltage measurement
Resistance measurement /
Continuity test / Diode test
CAP Capacitance measurement
μA mA A DC / AC current measurement
℃Temperature measurement
LCD Symbols（see Figure 2）
Figure 2
No. Symbol Description
1 Low battery indicator
2 - Negative
3 ACV or ACA measurement
4 DCV or DCA measurement

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5 TRms True RMS
6 Auto Range
7 RS232 Not used
8 Data hold mode
9 RELΔ Relative value measurment mode
10 ℃℉℃, ℉Temperature measurement
11 hFE Not used
12 Diode test mode / Continuity test mode
Hz KHz
MHz Frequency unit
13
% Duty cycle measurement
14 Ω KΩ
MΩ Resistance unit
nF μF Capacitance unit
mV V Voltage unit
15 mA μA
A Current unit
Measurement Operation
DC Voltage Measurement（see Figure 3）
To measure DC voltage, connect the Meter as follows:
·Set the rotary switch to desired or position.
·Connect the RED test lead into “VΩ” input terminal and
BLACK test lead into “COM” input terminal.

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·Connect the test leads across with the object being
measured.
·Read the value from display.
Warning
a) To avoid harms to you or damages to the Meter from
eletric shock, do not attempt to measure voltages higher
than DC 1000V or AC 750Vrms, 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.
Figure 3

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AC Voltage Measurement（see Figure 4）
To measure AC voltage, connect the Meter as follows:
·Set the rotary switch to position.
·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).
Warning
a) To avoid harms to you or damages to the Meter from
eletric shock, do not attempt to measure voltages higher
than DC 1000V or AC 750Vrms, 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.

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Figure 4
DC/AC current Measurement（see Figure 5）
To measure DC/AC current, connect the Meter as follows:
·Set the rotary switch to desired μA, mA or A position.
·Connect the RED test lead into “μAmA” or “10A” input
terminal and BLACK test lead into “COM” input terminal.
·Press Yellow button (function select) to select DCA or ACA
measuring mode.
·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).
Warning

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a) If magnitude of the current is unknown, always
start with the highest range and reduce until satisfactory
reading is obtained.
b) If “OL” or “-OL” is shown on the LCD, it means the
Meter is overloaded, then set the measuring range to
higher.
c) The protection of μAmA input terminal : Self-Healing
Fuse, and 10A range is F10A/250V.
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.

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Figure 5
Resistance Measurement（see Figure 6）
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, 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.
·Press Yellow button (function select) to select Ωmeasuring

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mode.
·Connect the test leads across with the object being
measured.
·Read the value from display.
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 “OL”.
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.
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.

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Figure 6
Diode Test（see Figure 7）
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.
·Press Yellow button (function select) to select

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measuring mode.
·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 0.5～0.8V.
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 “OL”.
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.