V&A MS8221 User manual

Pocket size digital multimeter
MS8221
Users Manual

CONTENTS
1 SAFETY INFORMATION..............................4
1.1 PRELIMINARY....................................4
1.2 DURING USE .....................................5
1.3 SYMBOL............................................6
1.4 MAINTENANCE ..................................7
2 DESCRIPTION ............................................7
3 SPECIFICATIONS .......................................9
3.1 GENERAL SPECIFICATIONS ................9
3.2 Measurement specifications.................10
3.2.1 DC VOLTAGE ................................... 11
3.2.2 AC VOLTAGE ................................... 11
3.2.3 DC CURRENT .................................. 12
3.2.4 AC Current (A/B/D model)................. 12
3.2.5 Resistance ........................................ 13
3.2.6 Diode test.......................................... 13
3.2.7 Audible continuity test ....................... 13

3.2.8 Audible continuity test (Only B model)14
3.2.9 Temperature (Only C model) ............. 14
4 OPERATING INSTRUCTION .....................15
4.1Voltage measurement .........................15
4.2 Current measurement .........................15
4.3 Resistance measurement ....................17
4.4 Diode test.........................................17
4.5 Continuity test ...................................18
4.6 Temperature measurement ..................18
(Only C model) ..........................................18
4.7 Battery test (only D model)...................19
4.8 Transistor measurement (only B model)
20
5 MAINTENANCE .........................................20
5.1 General Maintenance .........................20
5.2 Fuse replacement ..............................21
5.3 Battery replacement ...........................22

1 SAFETY
INFORMATION
WARNING
To ensure safe operation, and in order to
exploit to the full the functionality of the meter,
please follow the directions in this section
carefully.
This multimeter has been designed according to
IEC61010 concerning electronic measuring
instruments with an overvoltage category CAT III
600V and pollution 2.
Follow all safety and operating instructions to ensure
that the meter is used safely and is kept in good
operating condition.
With proper use and care, the digital meter will give
you years of satisfactory service.
1.1 PRELIMINARY
- When using the meter, the user must observe
all normal safety rules concerning:
Protection against the dangers of electrical
current.
Protection of the meter against misuse.
- When the meter is delivered, check that it has not
been damaged in transit.

- When poor condition under harsh preservation or
shipping conditions caused, inspect and confirm
this meter without delay.
- Test leads must be in good condition. Before using
verify that the insulation on test leads is not
damaged and/or the leads wire is not exposed.
- Full compliance with safety standards can be
guaranteed only if used with test leads supplied. If
necessary, they must be replaced with the same
model or same electric ratings.
1.2 DURING USE
- Before using, you must select the right input jack,
function and range.
- Never exceed the protection limit values indicated
in specifications for each range of measurement.
- When the value scale to be measured is unknown
beforehand, set the range selector at the highest
position.
- Do not measure voltage if the voltage on the
terminals exceeds 600V above earth ground.
- Always be careful when working with voltages
above 60V DC or 30V AC rms, keep fingers
behind the probe barriers while measuring.
- Before rotating the transform switch to change
functions and ranges, disconnect test leads from

the circuit under test.
- Never perform resistance, temperature, diode and
continuity measurements on live circuits.
- Never use the meter under the condition of the
explosive air, steam or dirt.
- If any faults or abnormalities are observed, the
meter can not be used any more and it has to be
checked out.
- Never use the meter unless the rear case is in
place and fastened fully.
- Please do not store or use meter in areas exposed
to direct sunlight, high temperature, humidity or
condensation.
1.3 SYMBOL
Caution:refer to the instruction manual.
Incorrect use may result in damage to the
device or its components.
Earth
This instrument has double insulation.
Fuse: F 2
50mA/600V 10A/600V

1.4 MAINTENANCE
- Please do not attempt to adjust or repair the meter
by removing the rear case while voltage is being
applied. A technician who fully understands danger
involved should only carry out such actions.
- Before opening the battery cover or case of the
meter, always disconnect test leads from all tested
circuits.
- To avoid the wrong reading causing electricity attack,
when the meter displays“ ”, you must change the
battery.
- For continue protection against fire, replace fuse
only with the specified voltage and current ratings: F
250mA/600V (quick acting),10A/600V (quick acting).
- Do not use abrasives or so5lvents on the meter, use
a damp cloth and mild detergent only.
- Always set the power switch to the OFF position
when the meter is not in use.
- If the meter is to be stored for a long period of time,
the batteries should be removed to prevent damage
to the unit.
2 DESCRIPTION
- This meter is a portable professional measuring
instrument with handsome LCD easily reading.

- Single operation of a transform switch makes
measurement convenient. Overload protection
and low battery indication are provided, this meter
is ideal for use in the fields, workshop, school,
hobby and home applications.
- This meter is with the functions of data hold.
NAME OF COMPONENTS
1. LCD display
2. Hold key
3. Rotary switch
4. Terminals

3 SPECIFICATIONS
3.1 GENERAL SPECIFICAT I ON S
- Environment conditions:
600V CAT.III
Pollution degree: 2. Altitude < 2000 m.
- Operating temperature:
0~40OC (32℉to 104℉), (<80% RH,
non-condensing)
- Storage temperature:
-10~50 OC(14℉to 122℉), (<70% RH, battery

removed)
- Temperature Coefficient:
0.1×(specified accuracy) / OC (<18 OC or >28 OC)
- MAX. Voltage between terminals and earth ground:
600V AC rms or 600V DC
- Fuse Protection: mA: F 250mA/600V ∅6.3×32,
10A: 10A/600V ∅6.3×32
- Display: LCD, 1999counts, updates 2-3/sec.
- Over Range indication: LCD will display "1".
- Low battery indication:
The " " is displayed on the LCD.
- Polarity indication: "−" displayed automatically.
- Power source: 9V
- Battery type: 6F22 9V
- Dimensions: 158(L)×74(W)×40(H) mm.
- Weight: 220g. Approx. (battery included).
3.2 Measurement specifications
Accuracy: ±(% of reading + number of digits) at 18°C
to 28°C (64°F to 82°F) with relative humidity to 80%.
(Accuracy is specified for a period one year after
calibration)

3.2.1 DC VOLTAGE
Range Resolution
Accuracy
A/B/D model
C model
0.2V
0.1mV
±0.5%±2
±0.5%±2
2V
1mV
±0.5%±3
±0.5%±3
20V
0.01V
±0.8%±3
200V
0.1V
600V
1V
±0.8%±2
±0.8%±5
- Input impedance: A/B/D model: 10MΩ
C model: 1MΩ
- Max. input voltage: 200mV range: 250VDC or AC
rms
2V - 600V ranges: 600VDC or 600V rms
3.2.2 AC VOLTAGE
Range Resolution
Accuracy
A/B/D model
C model
2V
1mV
±0.8%±4
-
20V
10mV
-
200V
0.01V
±1.2%±5
600V
1V
±1.2%±3
- Input impedance: A/B/D model: 10MΩ
C model: 1MΩ
- Max. input voltage: 200mV range: 250VDC or AC
rms

2V -600V ranges: 600VDC or 600V rms
- Frequency range: A/B/D model: 40Hz-1000Hz
C model: 40Hz-400Hz
- Response: Average, calibrated in rms of sine wave.
3.2.3 DC CURRENT
Range Resolution
Accuracy
A/B model
D model
C model
200uA
0.1uA
±0.8%±2
NULL
NULL
2mA
1 uA
±0.8%±2 ±1.5%±2
20mA
10 uA
200mA
100uA
±1.2%±2
10A
10mA
±2.0%±5
±3.0%±2
Overload protection: F250mA/600V 10A/600V.
Max. Input Current: mA Jack: 200mA, 10A Jack: 10A
3.2.4 AC Current (A/B/D model)
Range
Resolution
Accuracy
2mA
1µA
±1.2%±3
20mA
10µA
200mA
0.1mA
±2.0%±3
10A
10mA
±3.0%±7
Overload protection: F250mA/600V 10A/600V.
Max. input current: mA: 200mA dc or 200mA ac rms
10A: 10A 15 sec. Max

Frequency Range: 40Hz-1kHz
Indication: Average (rms of sine wave)
3.2.5 Resistance
Range Resolution
Accuracy
A/B/D model
C model
200Ω
0.1Ω
±0.8%±3
±1.0%±3
2KΩ
1Ω
±0.8%±2 ±1.0%±2
20KΩ
10Ω
200KΩ
100Ω
2MΩ
1kΩ
20MΩ
10kΩ
±1.0%±2
-
Overload protection: 250V DC or 250V AC rms.
3.2.6 Diode test
Display: read approximate forward voltage of
diode
Forward DC Current: approx. 1mA
Reversed DC Voltage: approx. 2.8V
Overload protection: 250V DC or 250V AC rms
3.2.7 Audible continuity test
Built-in buzzer sounds if resistance is less than
approx. 50Ω.
±0.8%±2
±1.0%±2

Open circuit voltage: approx. 2.8V
Overload protection: 250V DC or 250V AC rms
3.2.8 Audible continuity test (Only B model)
Range
Description
Test Condition
hFE
Display read approx.
HFE value (0-
1000) of
transistor under test (all
type).
Base Current
approx. 10μA,
Vce approx.
2.8V.
3.2.9 Temperature (Only C model)
Range
Resolution
Accuracy
-20
℃
to 0
℃
±5.0%±4
0
℃
to 400
℃
1
℃
±1.0%±3
400
℃
to 1000
℃
±2.0%±3
- Overload Protection: 250V DC or rms AC
3.2.10 Battery Test (Only D model)
Range
Accuracy
Discharge current
1.5V
±0.8%±2
100mA
9V
6mA
Overload protection: 1.5V: F250mA/600V fuse
9V: 250Vdc or 250Vac rms

4 OPERATING
INSTRUCTION
4.1 Voltage measurement
- Set rotary switch to the desired V or V~ range.
- Connect the black and red test leads to the COM
and V terminals respectively.
- Connect the test leads to the circuit being measured
- Read the displayed value. The polarity of red test lead
connection will be indicated when making a DCV
measurement.
- When only the figure “1” is displayed, it indicates
overrange situation and the higher range has to be
selected.
To avoid electrical shock and/or damage to
the instrument, do not attempt to take any
voltage measurement that might exceeds
6
00Vdc or 600Va
c rms. Do not apply more
than 6
00Vdc or 60
0Vac rms between the
common terminal and the earth ground.
4.2 Current measurement
- Set the rotary switch to the desired A or A~
range.
- Connect the black test lead to the COM terminal and

the red test leads to the mA terminal for a maximum
of 200mA. For a maximum of 10A, move the red
test lead to the 10A terminal.
- Connect test leads in series with the load in which
the current is to be measured.
- Read the displayed value. The polarity of red test
lead connection will be indicated when making a
DCA measurement.
- When only the figure "1" displayed, it indicates
overrange situation and the higher range has to be
selected.
* C model don’t have ACA measurement function.
To avoid damage to the meter, use the proper
terminals, function, and range for your
measurement.
NOTE:
- When only the figure ‘OL’ is displayed, it indicates
overrange situation and the higher range has to be
selected.
- When the value scale to be measured is unknown
beforehand, set the range selector at the highest
position.
- “ ” means the socket of INPUT maximum current
is 200mA, over current will destroy the fuse. 10A’s
maximum current is 10A, load 15sec each 10min.

4.3 Resistance measurement
- Connect the black test lead to the COM jack and
the red test lead to the Ωjack.
- Set the transform switch at the Ωrange position.
- Connect test leads across the resistance under
measurement.
- You can get reading from LCD.
To avoid electrical shock and/or damage to
the instrument, disconnect circuit power and
discharge all high
-voltage capacitors before
measuring resistance.
NOTE:
- For measuring resistance above 1MΩ, the meter
may take a few seconds to stabilize reading. This is
normal for high resistance measuring.
- If the resistance being measured exceeds the
maximum value of the range selected or the input is
not connected, an overrange indication "1" will be
displayed..
4.4 Diode test
- Set the rotary switch to range.
- Connect the black and red test leads to the COM
and Ωterminals respectively.
- Connect the red test lead to the anode, black test
lead to the cathode of the diode under testing.

- The meter will show the approx. forward voltage of
the diode. If the lead connection is reversed, only
figure "1" displayed.
To avoid electrical shock and/or damage to
the instrument, disconnect circuit power and
discharge all high
-voltage capacitors before
testing diodes.
4.5 Continuity test
- Set the rotary switch to range.
- Connect the black and red test leads to the COM
and Ωterminals respectively.
- Connect the test leads to the resistance in the circuit
being measured.
- When the test lead to the circuit is below 50Ω, a
continuous beeping will indicate it.
To avoid electrical shock and/or damage to
the instrument, disconnect circuit power and
discharge all high
-voltage capacitors before
testing for Continuity.
4.6 Temperature measurement
(Only C model)
- Set the transform switch at the TEMP range
position.

- The LCD display will show the current environment
temperature.
- When measuring the temperature with
thermocouple, ‘K’ type probe for this meter can be
used. Insert the black plug to the COM jack and
the red one to the TEMP jack, touch the end of the
temperature sensor to the area or surface of the
object for measurement.
- You can get reading from LCD.
To avoid electrical shock, do not connect the
thermocouples with the electriferous circuit.
4.7 Battery test (only D model)
- Set the rotary switch to desired BATT.range.
- Connect the black and red test leads to the COM
and VΩterminals respectively.
- Connect the test leads across the battery terminals
under measurement.
- Read LCD display and determine if the battery is
OK.

4.8 Transistor measurement
(only B model)
To avoid electrical shock and/or damage to the
instrument, before attempting to insert
tran
sistors for testing, always be sure that test
leads have been disconnected from any
measurement circuits
．
Set the rotary switch to hFE range, plug the
transistor adpertor.
Determine whether the transistor to be tested is
NPN or PNP type and locate the Emitter, Base and
Collector leads.
Insert leads of the transistor into proper holes of the
hFE socket.
The meter will show the approx. hFE value at test
condition of base current 10μA and Vce 2.8V.
5 MAINTENANCE
5.1 General Maintenance
Periodically wipe the case with a damp cloth and mild
detergent. Do not use abrasives or solvents.
Dirt or moisture in the terminals can affect readings.
To clean the terminals:
Turn the meter off and remove all test leads.
Shake out any dirt that may be in the terminals.