Mastech My68 User manual

HANDHELD

DIGITAL

DIGITAL MULTIMETER

MULTIMETER

OPERATOR

OPERATOR ’

’

’ S

S

INSTRUCTION

INSTRUCTION MANUAL

MANUAL

Table

Table of

of

of Contents

Contents

TITLE

TITLE PAGE

PAGE

1.

1. GENERAL

GENERAL

GENERAL INSTRUCTIONS

INSTRUCTIONS

INSTRUCTIONS 1

1

1.1 Precaution safety measures 1

1.1.1 Preliminary 1

1.1.2 During use 2

1.1.3 Symbols 4

1.1.4 Instructions 5

2.

2. DESCRIPTION

DESCRIPTION

DESCRIPTION 6

6

2.1 Instrument Familiarization

6

2.2 LCD Display

7

2.3 Key pad

9

2.4 Rotary switch

10

2. 5 Terminals

11

2. 6 Accessories

11

3.

3. FUNCTION

FUNCTION

FUNCTION DESCRIPTION

DESCRIPTION

DESCRIPTION 1 2

3.1 General Functions 1 2

3.1.1

DATA

HOLD mode 1 2

3.1.2 Manual ranging and Autorange mode 12

3.1. 3 Battery saver 1 3

3.2 Measurement Functions 1 3

3.2.1 AC and DC Voltage measurement 1 3

3.2.2 Resistance measurement 1 4

3.2.3 Diode

Test

1 6

3.2.4 Continuity Check

1 7

3.2.5 Capacitance measurement

1 7

3.2.6 Frequency measurement

1 8

3.2.7 Transistor measurement

1 9

3.2.8 Current measurement (with clamp,optional) 1 9

3.2.9 Current measurement

20

Ⅰ

Table

Table of

of

of Contents

Contents

TITLE

TITLE PAGE

PAGE

4.

4. TECHNICAL

TECHNICAL

TECHNICAL SPECIFICATIONS

SPECIFICATIONS

SPECIFICATIONS 21

21

4.1 General specifications..

21

4.2 Measurement specifications

22

4.2.1 DC Voltage

22

4.2.2 AC Voltage

22

4.2.3 Resistance

23

4.2.4 Diode

Test

23

4.2.5 Continuity Check

23

4.2.6 Transistor

23

4.2.7 Capacitance

24

4.2.8 Frequency

24

4.2.9 Current (with clamp, optional)

2 4

4.2.10 DC Current

25

4.2.11 AC Current

25

5.

5. MAINTENANCE

MAINTENANCE

MAINTENANCE 26

26

5.1 General maintenance

26

5.2 B attery and fuse replacement 26

6

6 .

.

. HOW

HOW

HOW TO

TO

TO USE

USE

USE THE

THE

THE HOLSTER

HOLSTER

HOLSTER 27

27

Ⅱ

1.

1. GENERAL

GENERAL

GENERAL INSTRUCTIONS

INSTRUCTIONS

This instrument complies with IEC 1010-1 (61010-1@IEC:

2001),

CAT.

II 1000V and

CAT.

III 600V overvoltage standards.

See Specifications.

To

get the best service from this instrument, read carefully this

user's manual and respect the detailed safety precautions.

International symbols used on the Meter and in this manual

are explained in chapter 1.1.3

1.1

1.1 Precautions

Precautions

Precautions safety

safety

safety measures

measures

1.1.1

1.1.1 Preliminary

Preliminary

* Measurement category III is for measurements performed in

the building installation.

NOTE: Examples are measurements on distribution boards,

circuit-breakers, wiring, including cables, bus-bars, junction

boxes, switches, socket-outlets in the fixed installation, and

equipment for industrial use and some other equipment, for

example, stationary motors with permanent connection to

the fixed installation.

* Measurement category II is for measurements performed on

circuits directly connected to the low voltage installation.

NOTE: Examples are measurements on household

appliances, portable tools and similar equipment.

* Measurement category I is for measurements performed on

circuits not directly connected to MAINS.

NOTE: Examples are measurements on circuits not derived

from MAINS, and specially protected (internal) MAINS

derived circuits. In the latter case, transient stresses are

variable; for that reason, requires that the transient

withstand capability of the equipment is made known to the

user.

1

* When using this Multimeter, the user must observe all

normal safety rules concerning:

― protection against the dangers of electric current.

― protection of the Multimeter against misuse.

* For your own safety, only use the test probes supplied with

the instrument. Before use, check that they are in good

condition.

1.1.2

1.1.2 During

During

During use

use

* If the meter is used near noise generating equipment, be

aware that display may become unstable or indicate large

errors.

* Do not use the meter or test leads if they look damaged.

* Use the meter only as specified in this manual; otherwise,

the protection provided by the meter may be impaired.

* Use extreme caution when working around bare conductors

or bus bars.

* Do not operate the meter around explosive gas,

vapor,

or dust.

* Verify a Meter's operation by measuring a known voltage.

Do not use the Meter if it operates abnormally. Protection

may be impaired. When in doubt, have the Meter serviced.

* Uses the proper terminals, function, and range for your

measurements.

* When the range of the value to be measured is unknown,

check that the range initially set on the multimeter is the

highest possible or, wherever possible, choose the

autoranging mode.

*

To

avoid damages to the instrument, do not exceed the

maximum limits of the input values shown in the technical

specification tables.

* When the multimeter is linked to measurement circuits, do

not touch unused terminals.

2

* Caution when working with voltages above 60Vdc or 30Vac

rms. Such voltages pose a shock hazard.

* When using the probes, keep your fingers behind the finger

guards.

* When making connections, connect the common test lead

before connecting the live test lead; when disconnecting,

disconnect the live test lead before disconnecting the

common test lead.

* Before changing functions, disconnect the test leads from

the circuit under test.

* For all dc functions, including manual or auto-ranging, to

avoid the risk of shock due to possible improper reading,

verify the presence of any ac voltages by first using the ac

function. Then select a dc voltage range equal to or greater

than the ac range.

* Before attempting to insert transistors for testing, always be

sure that test leads have been disconnected from any

measurement circuits ．

* Components should not be connected to the hFE socket

when making voltage measurements with test leads ．

* Disconnect circuits power and discharge all high-voltage

capacitors before testing resistance, continuity, diodes, or

capacitance.

* Never perform resistance or continuity measurements on

live circuits.

* Before measuring current, check the meter's fuse and turn

off power to the circuit before connecting the meter to the

circuit.

* In TV repair work, or when carrying out measurements on

power switching circuits, remember that high amplitude

voltage pulses at the test points can damage the multimeter.

Use of a TV filter will attenuate any such pulses.

3

* Use the 9V NEDA battery, properly installed in the Meter's

battery case, to power the Meter.

* 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.

* Do not measure voltages above 600V in Category III, or

1000V in Category II installations.

* Do not operate the Meter with the case (or part of the case)

removed.

1.1.3

1.1.3 Symbols:

Symbols:

Symbols used in this manual and on the instrument:

Caution

:

:refer to the instruction manual. Incorrect

use may result in damage to the device or its

components.

Dangerous voltage may be present.

~

AC (Alternating Current)

DC (Direct Current)

Earth ground

Double insulated

Fuse

Conforms to European Union directives

4

1.1.4

1.1.4 Instructions

Instructions

* Remove test leads from the Meter before opening the Meter

case or battery cover.

* When servicing the Meter, use only specified replacement

parts.

* Before opening up the instrument, always disconnect from

all sources of electric current and make sure you are not

charged with static electricity, which may destroy internal

components.

* Any adjustment, maintenance or repair work carried out on

the meter while it is live should be carried out only by

appropriately qualified personnel, after having taken into

account the instructions in this present manual.

* A "qualified person" is someone who is familiar with the

installation, construction and operation of the equipment

and the hazards involved. He is trained and authorized to

energize and de-energize circuits and equipment in

accordance with established practices.

* When the instrument is opened up, remember that some

internal capacitors can retain a dangerous potential even

after the instrument is switched off.

* If any faults or abnormalities are observed, take the

instrument out of service and ensure that it cannot be used

until it has been checked out.

* If the meter is not going to be used for a long time, take out

the battery and do not store the meter in high temperature or

high humidity environment.

5

2.

2. DESCRIPTION

DESCRIPTION

2.1

2.1 Instrument

Instrument

Instrument Familiarization

Familiarization

①Range Control Button

②Data Hold Button

③AC/DC Current or / Selecting Button

④Socket for Transistor

Test

⑤Function Switch/Power Switch

⑥V/ Ω /F/Cx Input Jack

⑦COM Input Jack

⑧mA/ Input Jack

⑨10A Input Jack

6

5

8

4

3

6

7

2

1

9

2.2

2.2 LCD

LCD

LCD Display

Display

See Table 1 indicated for information about the LCD display.

AC

Table

Table 1.

1.

1. Display

Display

Display Symbols

Symbols

Symbol

Symbol Meaning

Meaning

The battery is low.

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.

Indicates negative readings.

Indicator for ac voltage or current.

AC voltage and current are displayed as the

average of the absolute value of the input,

calibrated to indicate the equivalent rms value

of a sine wave.

Indicator for dc voltage or current.

AUTO

The Meter is in the Autorange mode in which

the meter automatically selects the range with

the best resolution.

7

Table

Table 1.

1.

1. Display

Display

Display Symbols

Symbols

Symbols (

(

( continued

continued

continued )

)

Symbol

Symbol Meaning

Meaning

Indicator for the Diode

Test

mode

hFE

Indicator for the t ransistor test mode

Indicator for the Continuity Check mode.

Indicator for the Data Hold mode

V,

mV

V:

mV:

Volts. The unit of voltage.

Millivolt. 1x10

-3

or 0.001 volts.

A,

A, mA,

mA,

mA, µ

µ

µA

A

A:

mA:

µA:

:

Amperes (amps). The unit of current.

Milliamp. 1x10

-3

or 0.001 amperes.

Microamp. 1x10

-6

or 0.000001

amperes

Ω

Ω,

,

, k

k

kΩ

Ω

Ω,

,

, M

M

MΩ

Ω

Ω:

kΩ:

MΩ:

Ohm. The unit of resistance.

Kilohm. 1x10

3

or 1000 ohms.

Megohm. 1x10

6

or 1,000,000 ohms.

Hz,

Hz, kHz,

kHz,

kHz, MHz

MHz

Hz:

KHz:

MHz:

Hertz. The unit of frequency in

cycles/second.

Kilohertz. 1x10

3

or 1000 hertz.

Megahertz. 1x10

6

or 1,000,000 hertz.

µ

F,

nF

F:

µF:

nF:

Farad. The unit of capacitance.

Microfarad.1x10

-6

or 0.000001

farads.

Nanofarad. 1x10

-9

or 0.000000001

farads.

The input is too large for the selected

range.

8

2.3

2.3 Keypad

Keypad

See Table 2 indicated for information about the keypad

operations.

Table

Table 2.

2.

2. Keypad

Keypad

Key

Key Function

Function

Function Operation

Operation

Operation performed

performed

A

A mA

mA

mA µ

µ

µA

A

Power-up

Power-up Option

Option

Switches between Diode

Test

and Continuity check.

Switches between dc and

ac current.

Disables automatic

power-off feature.

DATA-H

DATA-H Any

Any

Any switch

switch

switch position

position

position Press HOLD

HOLD

HOLD to enter and

exit the Data Hold mode.

RANGE

V~,

V~, V

V

V ,

,

,Ω

Ω

Ω,

,

, ,

,

mA

mA and

and

and µ

µ

µA.

A.

1. Press RANGE

RANGE

RANGE to enter

the manual ranging

mode.

2. Press RANGE

RANGE

RANGE to step

through the ranges

available for the

selected function.

3. Press and hold RANGE

RANGE

for 2 seconds to return to

autoranging.

9

2.4

2.4 Rotary

Rotary

Rotary switch

switch

See Table 3 indicated for information about the rotary switch

positions.

Table

Table 3.

3.

3. Rotary

Rotary

Rotary Switch

Switch

Switch Positions

Positions

Switch

Switch Position

Position

Position Function

Function

V~

V~ AC Voltage measurement

V

VDC Voltage measurement

Ω

ΩResistance measurement

Diode Test / Continuity Check

Cap

Cap Capacitance measurement

Hz

Hz Frequency measurement

hFE

hFE Transistor measurement

Measurement with clamp (optional),

widening the field of applications of

the multimeter

µ

µA

A

ADC or AC current measurements

from 0.1 µA to 4000 µA.

mA

DC or AC current measurements

from 0.01mA to 400mA.

A

DC or AC Current measurement from

0.01A to 10.00A.

10

2.5

2.5 Terminals

Terminals

See Table 4 indicated for information about the terminals.

Table

Table 4.

4.

4. Terminals

Terminals

Terminal

Terminal Description

Description

COM

Return terminal for all measurements.

（Receiving the black test lead or the “ com ”

plug of the optional clamp ）

V

VΩ

Ω

ΩFCx

FCx

Input for voltage, resistance, frequency,

Capacitance, diode and continuity

measurements. (Receiving the red test lead)

mA

Input for 0.1 µ

A

to 400mA current

measurements. （Receiving the red test lead or

the “ + ” plug of the optional clamp ）

A

Input for 400mA to 10A current measurements.

(Receiving the red test lead)

2.6

2.6 Accessories

Accessories

Delivered with the multimeter:

¥User's manual

¥Carry case

¥

Test

leads

¥Holster

Optional:

¥Clamp

11

3.

3. FUNCTION

FUNCTION

FUNCTION DESCRIPTION

DESCRIPTION

3.1

3.1 General

General

General Functions

Functions

3.1.1

DATA

HOLD

HOLD mode

mode

Data Hold mode makes the meter stop updating the display.

Enabling Data Hold function in autorange mode makes the

meter switch to Manual ranging mode, but the full-scale

range remains the same. Data Hold function can be

cancelled by changing the measurement mode, pressing

RANGE

RANGE key, or push HOLD

HOLD

HOLD key again.

To

enter and exit the Data Hold mode:

1. Press HOLD

HOLD

HOLD key (short press). Fixes the display on the

current value, “ H

H

H ””

””

”” is displayed.

2.

A

second short press returns the meter to normal mode.

3.1.2

3.1.2 Manual

Manual

Manual ranging

ranging

ranging and

and

and Autorange

Autorange

Autorange mode

mode

The Meter has both manual ranging and autorange

options.

* 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 ranging 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.

When the Meter is in the autorange mode, AUTO

AUTO

AUTO is

displayed.

To

enter and exit the manual range mode:

1. Press RANGE

RANGE

RANGE key. The Meter enters the manual

ranging mode. AUTO

AUTO

AUTO turns off. Each presses of RANGE

RANGE

key increments the range. When the highest range is

reached, the Meter wraps to the lowest range.

12

NOTE: If you manually change the measurement range after

entering the Data Hold modes, the Meter exits this

mode.

2.

To

exit the manual ranging mode, press and hold down

RANGE

RANGE key for two seconds. The Meter returns to the

autorange mode and AUTO

AUTO

AUTO is displayed.

3.1.3

3.1.3 Battery

Battery

Battery Saver

Saver

The Meter enters the "sleep mode" and blanks the display

if the Meter is on but not used for 30 minutes.

Press the HOLD

HOLD

HOLD key or rotate the rotary switch to wake

the meter up.

To

disable the Sleep mode, hold down the key

while turning the meter on.

3.2

3.2 Measurement

Measurement

Measurement Functions

Functions

3.2.1

3.2.1 AC

AC

AC and

and

and DC

DC

DC Voltage

Voltage

Voltage measurement

measurement

To

To avoid

avoid

avoid electrical

electrical

electrical shock

shock

shock and/or

and/or

and/or damage

damage

damage to

to

to the

the

instrument,

instrument, do

do

do not

not

not attempt

attempt

attempt to

to

to take

take

take any

any

any voltage

voltage

measurement

measurement that

that

that might

might

might exceed

exceed

exceed 1000Vdc

1000Vdc

1000Vdc or

or

750Vac

750Vac rms.

rms.

To

To avoid

avoid

avoid electrical

electrical

electrical shock

shock

shock and/or

and/or

and/or damage

damage

damage to

to

to the

the

instrument,

instrument, do

do

do not

not

not apply

apply

apply more

more

more than

than

than 1000Vdc

1000Vdc

1000Vdc or

or

750Vac

750Vac rms

rms

rms between

between

between the

the

the common

common

common terminal

terminal

terminal and

and

the

the earth

earth

earth ground.

ground.

The polarity of ac (alternating current) voltage varies over

time; the polarity of dc (direct current) voltage is constant.

The Meter's DC voltage ranges are 400.0mV, 4.000V,

40.00V, 400.0V and 1000V ；AC voltage ranges are

400.0mV , 4.000V, 40.00V, 400.0V and 750V.

(AC 400.0mV range only exists in manual ranging mode).

13

To

measure ac or dc voltage:

1. Set rotary switch to the DCV or ACV range.

2. Connect the black and red test leads to the COM and

V terminals respectively.

3. Connect the test leads to the circuit being measured

4. Read the displayed value. The polarity of red test lead

connection will be indicated when making a DCV

measurement.

NOTE:

¥Unstable display may occur especially at 400mV range,

even though you do not put test leads into input terminals,

in this case, if an erroneous reading is suspected, short

the V terminal and the COM terminal, and make sure the

zero display.

¥For better accuracy when measuring the dc offset of an

ac voltage, measure the ac voltage first. Note the ac

voltage range, then manually select a dc voltage range

equal to or higher than the ac range. This improves the

accuracy of the dc measurement by ensuring that the

input protection circuits are not activated.

3.2.2

3.2.2 Resistance

Resistance

Resistance measurement

measurement

To

To avoid

avoid

avoid electrical

electrical

electrical shock

shock

shock and/or

and/or

and/or damage

damage

damage to

to

to the

the

instrument,

instrument, disconnect

disconnect

disconnect circuit

circuit

circuit power

power

power and

and

discharge

discharge all

all

all high-voltage

high-voltage

high-voltage capacitors

capacitors

capacitors before

before

measuring

measuring resistance.

resistance.

The unit of resistance is the ohm ( Ω). The Meter measures

resistance by sending a small current through the circuit.

Because this current flows through all possible paths

between the probes, an in-circuit resistance reading

represents the total resistance of all paths between the

probes.

14

The Meter's resistance ranges are 400.0 Ω, 4.000k Ω,

40.00k Ω, 400.0k Ω, 4.000M Ωand 40.00M Ω.

To

measure resistance:

1. Set the rotary switch to Ω

Ω

Ωrange.

2. Connect the black and red test leads to the COM and

Ωterminals respectively.

3. Connect the test leads to the circuit being measured

and read the displayed value.

Some tips for measuring resistance:

¥The measured value of a resistor in a circuit is often

different from the resistor's rated value. This is because

the Meter's test current flows through all possible paths

between the probe tips.

¥In order to ensure the best accuracy in measurement of low

resistance, short the test leads before measurement and

memory the test probe resistance in mind. This necessary to

subtract for the resistance of the test leads.

¥The resistance function can produce enough voltage to

forward-bias silicon diode or transistor junctions, causing

them to conduct.

To

avoid this, do not use the 40M Ωrange

for in-circuit resistance measurements.

¥On 40M Ωrange, the meter may take a few seconds to

stabilize reading. This is normal for high resistance

measuring.

¥When the input is not connected, i.e. at open circuit,

the figure "OL" will be displayed for the overrange

condition.

15

3.2.3

3.2.3 Diode

Diode

Diode Test

Test

To

To avoid

avoid

avoid electrical

electrical

electrical shock

shock

shock and/or

and/or

and/or damage

damage

damage to

to

to the

the

instrument,

instrument, disconnect

disconnect

disconnect circuit

circuit

circuit power

power

power and

and

discharge

discharge all

all

all high-voltage

high-voltage

high-voltage capacitors

capacitors

capacitors before

before

testing

testing diodes.

diodes.

Use the diode test to check diodes, transistors, and other

semiconductor devices. The diode test sends a current

through the semiconductor junction, then measures the

voltage drop across the junction, A good silicon junction

drops between 0.5V and 0.8V.

To

test a diode out of a circuit:

1. Set the rotary switch to range.

2. Press the /

/

/key to activate Diode Test.

3. Connect the black and red test leads to the COM and

VΩterminals respectively.

4. For forward-bias 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.

5. The meter will show the approx. forward voltage of the

diode.

In a circuit, a good diode should still produce a forward bias

reading of 0.5V to 0.8V; however, the reverse-bias reading

can vary depending on the resistance of other pathways

between the probe tips.

16

3.2.4

3.2.4 Continuity

Continuity

Continuity Check

Check

To

To avoid

avoid

avoid electrical

electrical

electrical shock

shock

shock and/or

and/or

and/or damage

damage

damage to

to

to the

the

instrument,

instrument, disconnect

disconnect

disconnect circuit

circuit

circuit power

power

power and

and

discharge

discharge all

all

all high-voltage

high-voltage

high-voltage capacitors

capacitors

capacitors before

before

testing

testing for

for

for Continuity.

Continuity.

Continuity is a complete path for current flow.

The beeper sounds if a circuit is complete. These brief

contacts cause the Meter to emit a short beep.

To

test for continuity:

1. Set the rotary switch to range.

2. Press the /

/

/key to activate Continuity Check.

3. Connect the black and red test leads to the COM and

Ωterminals respectively.

4. Connect the test leads to the resistance in the circuit

being measured.

5. When the test lead to the circuit is below 50 Ω, a

continuous beeping will indicate it.

Note:

¥Continuity test is available to check open/short of the

circuit.

3.2.5

3.2.5 Capacitance

Capacitance

Capacitance measurement

measurement

To

To avoid

avoid

avoid electrical

electrical

electrical shock

shock

shock and/or

and/or

and/or damage

damage

damage to

to

to the

the

instrument,

instrument, disconnect

disconnect

disconnect circuit

circuit

circuit power

power

power and

and

discharge

discharge all

all

all high-voltage

high-voltage

high-voltage capacitors

capacitors

capacitors before

before

measuring

measuring capacitance.

capacitance.

capacitance. Use

Use

Use the

the

the dc

dc

dc voltage

voltage

function

function to

to

to confirm

confirm

confirm that

that

that the

the

the capacitor

capacitor

capacitor is

is

discharged.

Capacitance is the ability of a component to store an

electrical charge.

17

The unit of capacitance is the farad (F). Most capacitors are

in the nanofarad to microfarad range. The Meter measures

capacitance by charging the capacitor with a known current

for a known period of time, measuring the resulting voltage,

then calculating the capacitance. The measurement takes

about 1 second per range.

The Meter's capacitance ranges are 4.000nF 40.00nF,

400.0nF, 4.000 µ

F,

40.00 µF and 200.0 µ

F.

To

measure capacitance:

1. Set the rotary switch to Cap

Cap

Cap range.

2. Connect the black and red test leads to the COM

COM

COM and Cx

Cx

terminals respectively.

3. Connect the test leads to the capacitor being measured

and read the displayed value.

Some

Some tips

tips

tips for

for

for measuring

measuring

measuring capacitance:

capacitance:

¥The meter may take a few seconds (200 µF range, 30

seconds) to stabilize reading. This is normal for high

capacitance measuring.

¥

To

improve the accuracy of measurements less than 4nF,

subtract the residual capacitance of the Meter and leads.

3.2.6

3.2.6 Frequency

Frequency

Frequency measurement

measurement

Do

Do not

not

not measure

measure

measure Frequency

Frequency

Frequency on

on

on high

high

high voltage

voltage

(>250V)

(>250V) to

to

to avoid

avoid

avoid electrical

electrical

electrical shock

shock

shock hazard

hazard

hazard and/or

and/or

damage

damage to

to

to the

the

the instrument.

instrument.

1. Set the rotary switch to Hz

Hz

Hz range.

2. Connect the black and red test leads to the COM and Hz

terminals respectively.

3. Connect the test leads across the source or load under

measurement, and read the displayed value.

Note:

¥In noisy environment, it is preferable to use shield cable for

measuring small signal.

18

3.2.7

3.2.7 Transistor

Transistor

Transistor measurement

measurement

To

To avoid

avoid

avoid electrical

electrical

electrical shock

shock

shock and/or

and/or

and/or damage

damage

damage to

to

to the

the

instrument,

instrument, before

before

before attempting

attempting

attempting to

to

to insert

insert

transistors

transistors for

for

for testing,

testing,

testing, always

always

always be

be

be sure

sure

sure that

that

that test

test

leads

leads have

have

have been

been

been disconnected

disconnected

disconnected from

from

from any

any

measurement

measurement circuits

circuits

．

1. Set the rotary switch to hFE

hFE

hFE range.

2. Determine whether the transistor to be tested is NPN or

PNP type and locate the Emitter, Base and Collector leads.

3. Insert leads of the transistor into proper holes of the hFE

socket.

4. The meter will show the approx. hFE value at test condition

of base current 10 μ A and Vce 2.8V.

3.2.8

3.2.8 Current

Current

Current measurement

measurement

measurement (with

(with

(with clamp,

clamp,

clamp, optional)

optional)

To

To avoid

avoid

avoid electrical

electrical

electrical shock

shock

shock and/or

and/or

and/or damage

damage

damage to

to

to the

the

instrument,

instrument, do

do

do not

not

not apply

apply

apply more

more

more than

than

than 250Vdc

250Vdc

250Vdc or

or

250Vac

250Vac rms

rms

rms between

between

between the

the

the terminal

terminal

terminal and

and

and the

the

COM

COM terminal.

terminal.

1. Set the rotary switch to the range.

2. Press /~

/~

/~ key to select DCA or ACA measuring mode.

3. Connect the leads of the clamp to the COM

COM

COM and

terminals of the meter.

4. Read the displayed value. The polarity of the V Ωterminal

connection will be indicated when making a DCA

measurement.

5. When only the figure “ OL " displayed, it indicates overrange

situation.

19

3.2.9

3.2.9 Current

Current

Current measurement

measurement

To

To avoid

avoid

avoid damage

damage

damage to

to

to the

the

the Meter

Meter

Meter or

or

or injury

injury

injury if

if

if the

the

fuse

fuse blows,

blows,

blows, never

never

never attempt

attempt

attempt an

an

an in-circuit

in-circuit

in-circuit current

current

measurement

measurement where

where

where the

the

the open-circuit

open-circuit

open-circuit potential

potential

to

to earth

earth

earth is

is

is greater

greater

greater than

than

than 250V.

250V.

To

To avoid

avoid

avoid damage

damage

damage to

to

to the

the

the meter,

meter,

meter, check

check

check the

the

the meter's

meter's

fuse

fuse before

before

before proceeding.

proceeding.

proceeding. Use

Use

Use the

the

the proper

proper

terminals,

terminals, function,

function,

function, and

and

and range

range

range for

for

for your

your

measurement.

measurement. Never

Never

Never place

place

place the

the

the probes

probes

probes in

in

in parallel

parallel

with

with a

a

a circuit

circuit

circuit or

or

or component

component

component when

when

when the

the

the leads

leads

leads are

are

plugged

plugged into

into

into the

the

the current

current

current terminals.

terminals.

The Meter's current ranges are 400.0 µA, 4000 µA, 40.00mA,

400.0mA, and 10.00A.

To

measure current:

1. Turn off power to the circuit. Discharge all high voltage

capacitors.

2. Set the rotary switch to the µA, mA or

A

range.

3. Press /

/

/~

~

~key to select DCA or ACA measuring mode.

4. Connect the black test lead to the COM terminal and the

red test leads to the mA terminal for a maximum of

400mA. For a maximum of 10A, move the red test lead

to the A terminal.

5. Break the circuit path to be tested.

Touch the black probe to the more negative side of the

break; touch the red probe to the more positive side of

the break. (Reversing the leads will give a negative

reading, but will not damage the Meter.)

6. Turn on power to the circuit; then read the display. Be

sure to note the measurement units at the right side of

the display ( µA, mA or A). When only the figure "OL"

displayed, it indicates overrange situation and the

higher range has to be selected.

20

7. Turn off power to the circuit and discharge all high voltage

capacitors. Remove the Meter and restore the circuit to

normal operation.

4

4 TECHNICAL

TECHNICAL

TECHNICAL SPECIFICATIONS

SPECIFICATIONS

4.1

4.1 GENERAL

GENERAL

GENERAL SPECIFICATIONS

SPECIFICATIONS

¥Environment conditions:

1000V

CAT.

II and 600V

CAT.

III

Pollution degree: 2

Altitude < 2000m

Operating temperature:

0~40 ℃, 32 ℉~122 ℉(<80% RH, <10 ℃non-condensing)

Storage temperature:

-10~60 ℃, 14 ℉~140 ℉(<70% RH, battery removed)

¥Temperature Coefficient:

0.1 ×(specified accuracy) / ℃(<18 ℃or >28 ℃)

¥MAX. Voltage between terminals and earth ground:

750V AC rms or 1000V DC.

¥Fuse Protection:

µA and mA: F 5 00mA/250V ∅5×20;

10A: F 10A/250V ∅6.3 ×32.

¥Sample Rate: 3 times/sec for digital data.

¥Display:

3 3/4 digits LCD display. Automatic indication of functions

and symbols.

¥Range selection: automatic and manual.

¥Over Range indication: LCD will display "OL".

¥Low battery indication:

The " " is displayed when the battery is under the

proper operation range.

¥Polarity indication: " −" displayed automatically.

¥Power source: 9V

21

¥Battery type: NEDA 1604, 6F22, or 006P.

¥Dimensions: 91(L) ×189(W) ×31.5(H) mm.

¥Weight: 310g. Approx. (battery included).

4.2

4.2 Measurement

Measurement

Measurement specifications

specifications

Accuracy is specified for one year after calibration, at

operating temperatures of 18 ℃to 28 ℃, with relative humidity

at 0% to 75%.

Accuracy specifications take the form of: ± (% of Reading +

Number of Least Significant Digits)

4.2.1

4.2.1 DC

DC

DC Voltage

Voltage

Range Resolution Accuracy

400mV 0.1mV

±（0.7% of rdg +2 digits ）4V 1mV

40V 10mV

400V 100mV

1000V 1V ± （0.8% of rdg +2 digits ）

Input impedance: 10M Ω

Max. input voltage: 1000Vdc or 750V ac rms.

4.2.2

4.2.2 AC

AC

AC Voltage

Voltage

Range Resolution Accuracy

400mV 0.1mV ± (3.0% of rdg + 3 digits)

4V 1mV

±（0.8% of rdg +3 digits ）40V 10mV

400V 100mV

750V 1V ± （1.0% of rdg +3 digits ）

Input impedance: 10M Ω

Max. input voltage: 1000Vdc or 750V ac rms.

Frequency Range: 40Hz-200Hz for 4V range, 40Hz-1kHz for

other ranges.

Response: Average, calibrated in rms of sine wave

22

4.2.3

4.2.3 Resistance

Resistance

Range Resolution Accuracy

400.0 Ω0.1 Ω

±（1.2%% of rdg +2 digits ）

4.000k Ω1Ω

40.00k Ω10 Ω

400.0k Ω100 Ω

4.000M Ω1k Ω

40.00M Ω10k Ω

±（2.0% of rdg +5 digits ）

Overload protection: 250V dc or 150Vac rms.

Open Circuit Voltage: approx. 250mV.

4.2.

4.2. 4

4

4 Diode

Diode

Range Resolution Function

1mV

Display read approx.

forward voltage of diode

Forward DC Current: approx. 1mA

Reversed DC Voltage: approx. 1.5V

Overload protection: 250Vdc or 150Vac rms.

4.2.

4.2. 5

5

5 Audible

Audible

Audible continuity

continuity

Range Continuity beeper

≤ 50 Ω

Open circuit voltage: approx.0.5V.

Overload protection: 250Vdc or 250Vac rms.

4

4 .2.

.2.

.2. 6

6

6 Transistor

Transistor

Range Description Test Condition

hFE

Display read approx. HFE

value (0-1000) of transistor

under test (all type).

Base Current

approx. 10 μ A,

Vce approx. 2.8V.

23

4.2.

4.2. 7

7

7 Capacitance

Capacitance

Range Resolution Accuracy

4nF 1pF ± (5.0% of rdg+5 digits)

40nF 10pF

± (3.0% of rdg+3 digits)

400nF 100pF

4µF 1nF

40 µF 10nF

200 µF 100nF

Overload protection: 250Vdc or 250Vac rms.

4

4 .2.

.2.

.2. 8

8

8 Frequency

Frequency

Range Resolution Accuracy

9.999Hz 0.001 Hz

± (2.0% of rdg+5 digits)

99.99Hz 0.01 Hz

999.9Hz 0.1 Hz

9.999kHz 1Hz

99.99kHz 10Hz

199.9kHz 100Hz

>200kHz 100Hz Unspecified @ >200kHz

Overload protection: 250V dc or 250V ac rms.

Input Voltage range: 0.6V-3V ac rms (Input voltage must be

enlarged with increasing frequency

under measurement)

Frequency Response: 10Hz-200kHz, sine wave.

0.5Hz-200kHz, square wave.

4

4 .2.

.2.

.2. 9

9

9 Current

Current

Current (with

(with

(with clamp,

clamp,

clamp, optional)

optional)

Range Resolution Accuracy

DC40A 0.1A/1mV ± (0.8% of rdg+3 digits)

DC400A 1A/1mV ± (0.8% of rdg+3 digits)

AC40A 0.1A/1mV ± (1.0% of rdg+3 digits)

AC400A 1A/1mV ± (1.0% of rdg+3 digits)

Input impedance: 1M Ω

Max. input voltage: 250Vdc or 250Vac rms.

24

4.2.

4.2. 10

10

10 DC

DC

DC CURRENT

CURRENT

Range Resolution

Accuracy

400 µA 0.1 µA

± (1.2% of rdg+3 digits)4000 µA 1 µA

40mA 0.01mA

400mA 0.1mA

10A 10mA

± (2.0% of rdg+5 digits)

Overload protection: F 10A/250V fuse for A range. F

5 00mA/ 2 50V fuse for µA and mA

ranges.

Maximum input current: 400mA dc or 400mA ac rms for µ

A

and mA ranges, 10A dc or 10A ac

rms for A ranges.

For measurements>5A, 4 minutes maximum ON to measure

10 minutes OFF.

4.2.1

4.2.1 1

1

1 AC

AC

AC CURRENT

CURRENT

Range Resolution

Accuracy

400 µA 0.1 µA

± (1.5% of rdg+5 digits)4000 µA 1 µA

40mA 0.01mA

400mA 0.1mA

10A 10mA

± (3.0% of rdg+7 digits)

Overload protection: F 10A/250V fuse for A range.

F 5 00mA/ 2 50V fuse for µ

A

and mA

ranges.

Maximum input current: 400mA dc or 400mA ac rms for µ

A

and mA ranges, 10A dc or 10A ac

rms for A ranges.

Frequency Range: 40Hz-1kHz

Response: Average, calibrated in rms of sine wave

25

5.

5. MAINTENANCE

MAINTENANCE

This section provides basic maintenance information,

including fuse and battery replacement instructions.

Do not attempt to repair or service your Meter unless you are

qualified to do so and have the relevant calibration,

performance test, and service information.

5.1

5.1 General

General

General Maintenance

Maintenance

To

To avoid

avoid

avoid electrical

electrical

electrical shock

shock

shock or

or

or damage

damage

damage to

to

to the

the

meter,

meter, do

do

do not

not

not get

get

get water

water

water inside

inside

inside the

the

the case.

case.

case. Remove

Remove

the

the test

test

test leads

leads

leads and

and

and any

any

any input

input

input signals

signals

signals before

before

opening

opening the

the

the case

case

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.

¥Soak a new swab with a cleaning and oiling agent (such as

WD-40).

¥Work the swab around in each terminal. The oiling agent

insulates the terminals from moisture-related contamination.

5.2

5.2 B

B

B attery

attery

attery and

and

and fuse

fuse

fuse replacement

replacement

If the sign “ ” appears on the LCD display, it indicates that

the battery should be replaced. Remove screws on the back

cover and open the case. Replace the exhausted battery with

a new one.

Fuse rarely need replacement and blow almost always as a

result of the operator

’

s error .Open the case as mentioned

above, and then take the PCB assembly out from the

case .Replace the blown fuse with ratings specified.

26

WARNING

Before attempting to open the case, be sure that test leads

have been disconnected from measurement circuits to avoid

electric shock hazard.

For protection against fire, replace fuse only with specified

ratings: F1: F 5 00mA/250V F2: F 10A/250V

6.

6. HOW

HOW

HOW TO

TO

TO USE

USE

USE THE

THE

THE HOLSTER

HOLSTER

The holster is used to protect the meter and to make the

measurement more comfortable. it comes with two stands

installed together. The following figure shows how to use the

holster to:

a. Support the meter with a standard angle.

b. Support the meter with a small angle using the little

stand

c. Hang the meter on the wall using the little stand. Take

the little stand off from the backside of the large stand

and insert it into holes located upper on the holster.

d. Hold test leads.

CAUTION:

“ Using this appliance in an environment with a strong radiated

radio-frequency electromagnetic field9approximately 3V/m),

may influence its measuring accuracy. The measuring result

can be strongly deviating from the actual value

”

27

Mastech my68 User manual

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