Tenma 72-7222 User manual

1
Model 72-7222: OPERATING MANUAL
Table of Contents
Title Page
Overview
Inspection
Safety Information
Rules For Safe Operation
International Electrical Symbols
The Meter Structure
Rotary Switch
Function Buttons
Function Button Use
Display Symbols
Measurement Operation
A. DC Voltage Measurement
B. AC Voltage Measurement
C. Measuring Resistance
D. Testing Diodes
E. Testing for Continuity
F. Temperature Measurement
G. AC Current Measurement
Sleep Mode
Specifications
A. General Specifications
B. Environmental Restriction
Accuracy Specifications
A. AC Voltage
B. DC Voltage
C. Resistance
D. Continuity Test
E. Diode Test
F. Temperature
G. AC Current
Maintenance
A. General Service
B. Replacing the Battery
3
4
5
6
8
9
10
11
12
13
15
15
16
17
19
20
22
23
25
26
26
26
27
27
27
28
28
28
29
29
30
30
30

Table of Contents
Title Page
Overview
Inspection
Safety Information
Rules For Safe Operation
International Electrical Symbols
The Meter Structure
Rotary Switch
Function Buttons
Function Button Use
Display Symbols
Measurement Operation
A. DC Voltage Measurement
B. AC Voltage Measurement
C. Measuring Resistance
D. Testing Diodes
E. Testing for Continuity
F. Temperature Measurement
G. AC Current Measurement
Sleep Mode
Specifications
A. General Specifications
B. Environmental Restriction
Accuracy Specifications
A. AC Voltage
B. DC Voltage
C. Resistance
D. Continuity Test
E. Diode Test
F. Temperature
G. AC Current
Maintenance
A. General Service
B. Replacing the Battery
Model 72-7222: OPERATING MANUAL
2

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.
The Digital Clamp Multimeter Model #72-7222 (hereafter
referred to as “the Meter”) is 3 1/2 digits with precise
operation, fashionable structure and highly reliable
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 measures AC/DC Voltage, AC Current,
Resistance, Temperature( ), Diodes and Continuity.
oF/ oC
Model 72-7222: OPERATING MANUAL
3

In the event you find any items missing or damaged,
please contact your dealer immediately.
Inspection
Open the package case and take out the Meter. Check
the following items carefully to see if any items are missing
or damaged.
Point Contact Temperature Probe
4 1.5V Battery (AAA) 2 pieces
Model 72-7222: OPERATING MANUAL
4
Item
1
2
3
Description
English Operating Manual
Test Lead
Qty
1 piece
1 pair
1 piece

Safety Information
This Meter complies with the standards IEC61010: in
pollution degree 2, overvoltage category (CAT. II 600V,
CAT. III 300V) 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.
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.
International electrical symbols used on the Meter and
in this Operating Manual are explained on page 8.
Model 72-7222: OPERATING MANUAL
5

Rules For Safe Operation (1)
l Before 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.
l Inspect 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.
l Do not apply more than the rated voltage, as
marked on the Meter, between the terminals or
between any terminal and ground. 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.
l Whenmeasurementhasbeencompleted,disconnect
the connection between the test leads and the
circuit under test, remove the test leads from the
input terminals of the Meter and turn the Meter
power off.
l The rotary switch should be placed in the correct
position and no change of range made during
measurement, to prevent damage to the Meter.
l Do not carry out the measurement when the
Meter’s back case and battery compartment are
not closed to avoid electric shock.
l Do not input higher than 600V between the Meter’s
terminals and the ground to avoid electric shock
and damage to the Meter.
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:
Warning
Model 72-7222: OPERATING MANUAL
6

Rules For Safe Operation (2)
l When working at an effective voltage over
60VDC or 30VAC RMS, special care should
be taken for there is danger of electric shock.
l Use the proper terminals, function, and range
for your measurements.
l Do 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.
l When using the test leads, keep your fingers
behind the finger guards.
l Disconnect circuit power and discharge all high
-voltage capacitors before testing resistance,
continuity and diode.
l Replace the battery as soon as the battery indicator
appears. With a low battery, the Meter might
produce false readings that can lead to electric
shock and personal injury.
l When servicing the Meter, use only the same
model number or identical electrical specifications
replacement parts.
l The internal circuit of the Meter shall not be altered
at will to avoid damage of the Meter and any
accident.
l Soft 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.
l The Meter is suitable for indoor use.
l Turn the Meter off when it is not in use and take
out the battery when not using for a long time.
l Periodically check the battery as it may leak
after some time. If leakage is apparent, the
battery should be immediately replaced to
prevent damage to the Meter.
Model 72-7222: OPERATING MANUAL
7

International Electrical Symbols
AC (Alternating Current).
DC (Direct Current).
AC or DC.
Ground.
Double Insulated.
Continuity Test.
Diode.
Fuse.
Warning. Refer to the Operating Manual.
Conforms to Standards of European Union.
Capacitance Test
Low Battery
Model 72-7222: OPERATING MANUAL
8

9
The Meter Structure (see figure 1)
( figure 1)
1. Input Terminals
2. LCD Display
3. Function Buttons
4. Rotary Switch
5. Trigger: press the lever to open the transformer jaws.
When the pressure on the lever is released, the jaws
will close.
6. Hand Guards: to protect user’s hand from touching
the dangerous area.
7. Transformer Jaws: designed to pick up theAC current
flowing through the conductor.
Model 72-7222: OPERATING MANUAL

Rotary Switch
The following table provides information regarding the
Rotary Switch positions.
Rotary
Switch
Position Function
AC/DC voltage measurement.
: Diode test.
: Resistance measurement.
Ω
Power is turned off.OFF
: Continuity test.
Ω
Temperature measurement
oCoF
AC current measurement range from 0.001A
to 400.0A
A
Model 72-7222: OPERATING MANUAL
10

Function Buttons(1)
AC voltage measurement.
l Press HOLD to enter and exit the
Hold mode in any mode, the Meter beeps.
l Press and hold HOLD button
while turning on the Meter to display
full icons.
HOLD
MAX Press MAX to start recording and updating
of maximum values.
SELECT Press SELECT button to switch between
and .
oCoF
Ω
Model 72-7222: OPERATING MANUAL
11
The following table provides information regarding
function button operations.

The Effectiveness of Function Button Use
Rotary Switch
Position SELECT MAX HOLD
V
VN/A
N/A
ΩN/A
N/A
A
A2/20A N/A
200/400A N/A
oFoC(K-Type)
Function Button
Model 72-7222: OPERATING MANUAL
12
Not every function button is used in every rotary switch
position. The table below indicates which button can
be used in which switch position.

Display Symbols(1) (see figure 2)
No. Symbol Meaning
3
Low battery.
Warning: To avoid false readings,
which could lead to possible electric
shock or personal injury, replace
the battery as soon as the battery
indicator appears.
4The Meter is in the auto range mode
in which the Meter automatically selects
the range with the best resolution.
5Diode test.
6The continuity buzzer is on.
7Date hold is active.
8
1 AC Indicator for AC voltage or current
2 DC Indicator for DC voltage
MAX Maximum reading displayed
The unit of temperature:
oC: Centigrade temperature
oF: Fahrenheit temperature
oCoF
9
Ω: Ohm. The unit of resistance.
kΩ: kilohm.1 x 103or 1000 ohms.
MΩ: Megaohm. 1 x 106or
1,000,000 ohms.
Ω,kΩ,MΩ
10
Model 72-7222: OPERATING MANUAL
13

No. Symbol Meaning
11 A Amperes (amps). The unit of current.
Display Symbols(2) (see figure 2)
mV, V Volts. The unit of voltage.mV: Millivolt.
1x10-3 or 0.001 volts
12
13 Indicates negative reading
14 OL The input value is too large for the
selected range
Model 72-7222: OPERATING MANUAL
14

Measurement Operation(1)
Warning
red black
( figure 3)
The DC Voltage ranges are:
200.0mV, 2.000V, 20.00V, 200.0V and 600V.
To measure DC voltage, connect the Meter as follows:
1. Insert the red test lead into the VΩterminal
and the black test lead into the COM terminal.
2. Set the rotary switch to V .
3. Connect the test leads across with the object being
measured.
The measured value shows on the display.
Note
l In each range, the Meter has an input impedance of
10MΩ. This loading effect can cause measurement
errors in high impedance circuits. If the circuit impedance
is less than or equal to 10kΩ, the error is negligible
(0.1 or less).
A. DC Voltage Measurement (see figure 3)
Model 72-7222: OPERATING MANUAL
15
To avoid damage to the meter, or risk of personal
injury, do not attempt to measure higher than 600V
AC/DC, although readings may be obtained.

Measurement Operation(2)
B. AC Voltage Measurement (see figure 4)
red black
( figure 4)
Warning
The AC Voltage ranges are:
2.000V, 20.00V, 200.0V and 600V.
To measure AC voltage, connect the Meter as follows:
1. Insert the red test lead into the VΩterminal
and the black test lead into the COM terminal.
2. Set the rotary switch to V
3. Connect the test leads across with the object being
measured.
The measured value shows on the display.
Model 72-7222: OPERATING MANUAL
16
When DC voltage measurement has been completed,
disconnect the test leads from the circuit under test,
and remove them from the input terminals.
To avoid damage to the meter, or risk of personal
injury, do not attempt to measure higher than 600V
AC/DC, although readings may be obtained.

Measurement Operation(3)
Note
l In each range, the Meter has an input impedance of
10MΩ. This loading effect can cause measurement
errors in high impedance circuits. If the circuit impedance
is less than or equal to 10kΩ, the error is negligible
(0.1 or less).
l When AC voltage measurement has been completed,
17
C.Measuring Resistance (see figure 5)
red black
( figure 5)
Warning
To avoid damage to the Meter or to the devices
under test, disconnect circuit power and discharge
all the high-voltage capacitors before measuring
resistance.
Model 72-7222: OPERATING MANUAL
disconnect the test leads from the circuit under test,
and remove them from the input terminals.

Measurement Operation(4)
The resistance ranges are:
200.0 , 2.000k , 20.00k ,200k ,2.000M and 20.00M .
To measure resistance, connect the Meter as follows:
1. Insert the red test lead into the Vterminal and
the black test lead into the COM terminal.
2. Set the rotary switch to ; resistance measurement
( ) is default or press SELECT button to select
measurement mode.
3. Connect the test leads across with the object being
measured.
The measured value shows on the display.
Note:
The test leads can add 0.1Ωto 0.3Ω of error to resistance
measurement.
l
l
l
l
l
l
For high-resistance measurement (>1M ), it normally
requires several seconds to obtain a stable reading.
If reading with shorted test leads is not 0.5 , check
for loose test leads, wrong function selected, or enabled
data hold function.
The LCD displays OL indicating open-circuit or the tested
resistor value is higher than the maximum range of the
Meter.
Resistance measurement is default to auto range mode.
Removing the object under test from its circuit will allow
more accurate measurement.
When resistance measurement has been completed,
disconnect the test leads from the circuit under test, and
remove them from the input terminals.
Model 72-7222: OPERATING MANUAL
18

Measurement Operation(5)
D.Testing Diodes (see figure 6)
red black
( figure 6)
Warning
To avoid damage to the Meter or to the devices under
test, disconnect circuit power and discharge all the
high-voltage capacitors before testing diodes.
Use the diode test to check diodes, transistors, and other
semiconductor devices. The diode test sends a current
through the semicondutor junction, then measure the
voltage drop across the junction. A good silicon junction
drops between 0.5V and 0.8V.
To test the diode out of a circuit, connect the Meter as
follows:
1. Insert the red test lead into the VΩterminal and
the black test lead into the COM terminal.
2. Set the rotary switch toΩ and press SELECT
button to select measurement mode.
3. For forward voltage drop readings on any semiconductor
component, place the red test lead on the component’s
anode and place the black test lead on the component’s
cathode.
Model 72-7222: OPERATING MANUAL
19

Measurement Operation(6)
Note
l 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.
l Connect the test leads to the proper terminals as
said above to avoid error display.
l The LCD will display OL indicating either open circuit
or wrong polarity connection.
l The unit of diode is volt (V), displaying the forward
voltage drop readings.
l Removing the object from its circuit will allow more
accurate measurement.
l When diode testing has been completed, disconnect
the test leads from the circuit under test, and remove
them from the input terminals.
E.Testing Continuity (see figure 7)
red black
( figure 7)
Model 72-7222: OPERATING MANUAL
20