Mastech MS8240B Operating Instruction

MS8240B

Digital Multimeter

FUNC

HOLD

MAX

FUSED FUSED

Digital Multimeter

Operating Instruction

MS8240B

1. Introduction

CONTENTS

5. Measurement Operation

5.1 DC & AC Voltage Measurement

5.2 Resistance Measurement

5.3 Diode/Continuity Check

5.4

5.5 Transistor Check

5.6 Frequency Measurement

5.7 DC/AC mA/10A Measurement

5.8 Inductance Measurement

5.9 Temperature Measurement

Capacitance Measurement

.............................................1

.........................10

....................10

2. Safety note

3. Product Overview

...............................................1

....................................3

3.1 Meter Illustration

3.2 Functional Push Button

3.3 Display Indicators

..................................3

.........................4

4. Specification

............................................5

4.1 General Feature

4.2 Electrical Specification

....................................5

..........................6

.......................11

..................12

.................................13

.....................14

.............15

....................16

..................16

6. Maintenance

...........................................19

6.1 Replacing The Battery

6.2 Fuse Replacement

6.3 Cleaning and Decontamination

...........................19

..............................19

............19

01

1. Introduction

This Met er is a han dheld a nd batt ery ope rated D igita l
Multi Meter (DMM) w ith mul ti func tion. Thi s Meter i s
designed to m eet IEC -6101 0-1 CAT III 1000 V over
voltage cat egory a nd doub le insu latio n. The enti re
oute r surfa ce of the c ase has b een for med wit h therm o
plastic ela stome r,givi ng the ma in body, tho ugh
downsized , high re sista nce aga inst th e shock o f a drop.
This operatin g instr uctio n cover s infor matio n on safe ty
and caution . Pleas e read re levan t infor matio n caref ully
and observe a ll the wa rning s and not e stric tly. Th e
DMM as g enera l measu remen t tool an d widel y used in
the sc hool, l abora tory, fact ory etc socia l field .

2. Safety Note

To avoid possib le elec tric sh ock or pe rsona l injur y and
to avoid poss ible da mage to t he mete r or to the
equipment under te st, adh ere to th e follo wing ru le:

Warning

..................................4

............10

• Do not apply mo re than t he rate d volta ge of mar ked
on the meter

• Do not apply vo ltage b etwee n COM and O HM
terminal, i n the res istan ce meas uring s tate.

• Do not measur e curre nt with t est lea d inser ted int o
voltage or OH M termi nal.

• Do not expose t he inst rumen t to the di rect su n light ,
extreme tem perat ure and h umidi ty or dew f ull.

• Inspect the t est lea d for dam aged in sulat ion or
exposed met al.

• Before meas uring c urren t, chec k the Met er's fu ses
and turn off powe r to the ci rcuit b efore c onnec ting
the meter to th e circu it.

FUNC

HOLD

MAX

FUSED FUSED

0302

Dangerous v oltag e Grounding

AC

(Alternating Current)

Double insu latio n

DC (Direct Cu rrent )

Fuse

3. Explanation of Controls and Indicators

3.1 Meter Illustration

FRONT PANEL

1

2

3

4

5

6

8

7

11

10

9

• Disconnec t circu it powe r and dis charg e all hig h

voltage cap acito rs befo re test ing con tinui ty, diode,
resistanc e, capa citan ce or cur rent.

Note intern ation al Elec trica l Symbo l.

AC or DC

Warning se e
explain in ma nual

(1) LCD Displ ay

(2) “MAX” pus h butto n　　　

(3) “HOLD” pu sh butt on
(4) Rotary Sw itch (K nob)
(5) “V. Ω. Hz” In put ter minal
(6) “COM” ter minal
(7) “μA.mA. °C.Cx .Lx.h FE”In put ter minal
(8) “10A” inp ut term inal
(9) Power swi tch(O N.OFF )
(10) “FUNC” p ush but ton
(11) “BKL IT” pus h butto n

04 05

3.2 Functional Push Button

“FUNC” key is t he func tion se lect ke y that
acts with tri gger. Us e the key a s switc h of
DC/AC volta ge,DC /AC cur rent ,
Resistanc e/Con tinui ty and °C /°F.

Press “HOLD ” to ente r and exi t the hol d
mode in any mod e. That act w ith tri gger.

This key is act w ith tri gger. Pr ess thi s key
once, the max imum va lue is ho lding ( Will
displays 'M AX' sym bol in th e LCD).
After press ing the k ey, A/D will keep
working, an d the dis play va lue are a lways
up dated and ke pt the ma ximum v alue.
(The actual g ained v alue is n ot the
peak value. ).

This key is use d to cont rol Bac kligh t.
This key is act w ith tri gger. Wh en pres s
the key, wi ll enab le Back light f or 15 sec .
Press the key a gain wi thin 15 s ec,
Backlight w ill dis able.

ON/OFF Lock t ype Pow er Swit ch.

FUNC

HOLD

MAX/MIN

Push button

Function

Back light
*

3.3 Display Indicators

FIG 2 LC D

Number

Indicator

Meaning

1

2
3

4

5
6

7

8

10

11
12
13
14

MAX

HOLD

Mk Ω

°C/°F

The unit of tem perat ure ( °C:
Centigrad e; °F: Fa hrenh eit)

9

µmVA

uV mV V is unit of vo ltage
uA mA A is unit of current

Indicate ne gativ e readi ng

Capacitan ce Indi cator

Cx

Lx
mH/H
nµmF

Inductanc e Indic ator
Inductanc e Units
Capacitan ce Unit s

Ω KΩ MΩ is u nit of re sista nce

Low battery i ndica tor

Data hold

Maximum val ue

Diode

AC voltage or c urren t

DC voltage or c urren t

06 0 7

4. Technical Specifications

4.1 General Specificatio ns

• Manual rang ing DMM , t hat ful l scale i s 1999 co unts

• Display : 3 1/2 d igit LC D displ ay.

• Over load pro tecti on: Use d the PTC p rotec tion

circuit for R esist ance, c apaci tance An d frequ ency
measureme nt.

• DATA HOLD funct ion

• MAX value mea surem ent fun ction

• Back Light

• Low battery i ndica tion

• Auto Power- O FF.

• Operating t emper ature & H umidi ty: 0 ~ 40° C

(32~104°F ) & < 80% RH

• Storage tem perat ure & Hum idity : -10 ~ 50° C
(14~122°F ) & <70%R H

• Power Suppl y: 1.5V B atter y(AA Type)× 4

• Safety Clas s: IEC- 61010 -1, 100 0V CAT II I,

600V CAT IV.

• Dimension ( L×W×H ) & We ight:
205 mm×102 mm ×58mm , Approx . 390g.

4.2 Electrical Specification( at 23±5 <75% RH)°C

4.2.1 DC volt age

Range

Resolutio n

Accuracy

200mV 0.1mV

2V

20V

200V

1000V

1mV

10mV

100mV

1V

±(0.5% rdg + 2dgt)

* Input imped ance: 1 0MΩ

* Over load pro tecti on: 250 V DC/AC (rms)
at 200mV Rang e.

* Max input vol tage: 1 000VD C

4.2.2 AC vol tage

Range

Resolutio n

Accuracy

200mV 0.1mV

2V

20V

200V

1000V

1mV

10mV

100mV

1V

±(0.8% rdg + 3dgt)

±(1.0% rdg + 5dgt)

* Input imped ance: 1 0MΩ
* Over load pro tecti on: 250 V DC/AC (rms)

at 200mV Range.

* Frequency r espon se: 40~ 400Hz
* Average rectif ier typ e.
* Max input vol tage: 7 50V AC rms

4.2.3 Resis tance

Range

Resolutio n

Accuracy

200Ω 0.1Ω

2kΩ

20kΩ

200kΩ

2MΩ

20MΩ

0.001kΩ

0.01kΩ

0.1kΩ

0.001MΩ

0.01MΩ

±(0.8% rdg + 3dgt)

±(1.5% rdg + 5dgt)

* Over load pro tecti on: 250 V DC/ AC rms

08 0 9

4.2.4 Diode

Range

Resolutio n

Function

0.001V

Will display the forward
drop voltage.

* Over load pro tecti on: 250 V DC/ AC rms

4.2.5 Conti nuity

Range

Function

If measured r esist ance le ss than 3 0Ω,
will buzzer i s sound ed.

* Over load pro tecti on: 250 V DC/ AC rms

4.2.6 DC Curr ent

Range

Resolutio n

Accuracy

2mA

20.00mA

200.0mA

10.00A

1µA

0.01mA

0.1mA

0.01A

(1.0% rdg + 3dgt)

(2.0% rdg + 3dgt)

* Over protection: use the fuse(F250mA/1KV)
at mA range, and use the fuse(F10A/1KV) at 10A range.
* Max input current: 200mA at 'mA' jack
and 10A at '10A' jack.

4.2.7 AC Cur rent

Range

Resolutio n

Accuracy

2mA

20mA

200.0mA

10.00A

1µA

0.01mA

0.1mA

0.01A

(1.5% rdg + 5dgt)

(3.0% rdg + 10dgt)

* Over protection:use the fuse(F250mA/1KV) at mA
range, and use the fuse(F10A/1KV) at 10A range.
* Max input current::200mA at 'mA' jack and
10A at '10A' jack.
* Frequency response:40 ~ 400Hz

4.2.8 Tem perat ure

You can selecting Ce nti-d egree [°C] or F ahren heit
[°F] b y “FUNC ” key.

Range

-20°C ~ 1000° C

-20°C~0°C

1°C

400°C~1000°C

* Over load pro tecti on: use t he fuse [ F250m A/1KV ].

(2.0% rdg + 3dgt)

Resolution

0°C~400°C

Fahrenheit Temperature [°F]

Accuracy

(1.0% rdg + 3dgt)

(5.0% rdg + 4dgt)

0°F~1800°F

Range

-0°F~50°F

1°F

750°F~1800°F

(2.0% rdg + 3dgt)

Resolution

50°F~750°F

Accuracy

(1.0% rdg + 3dgt)

(5.0% rdg + 4dgt)

10 11

4.2.9 Capac itanc e

Range

Resolutio n

Accuracy

2nF

0.001nF

±(4.0%rdg +5dgt)

20nF

200nF

2µF

20µF

0.01nF

0.1nF

0.001nF

0.01µF

* Over load pro tecti on: use t he fuse [F250 mA/1K V]

200µF

0.1µF

±(5.0%rdg +10dgt)

4.2.10 hFE

Range

Function

hFE: 1~1000

hFE

* Over load pro tecti on: use t he fuse [ F250m A/1KV ]

4.2.11 Frequ ency

* Sensitivi ty: 200 mV -5V AC rm s
* Over load pro tecti on: 250 V DC/AC r ms

Range

Resolutio n

Accuracy

20kHZ 1HZ

±(1.5%rdg +5dgt )

4.2.12 Indu ctanc e

Range

Resolutio n

Accuracy

2mH

0.001mH

±(4.0%rdg +8dgt)

20mH

200mH

2H

0.01mH

0.1mH
1mH

20H

10mH

±(4.0%rdg +3dgt)
±(4.0%rdg +3dgt)
±(4.0%rdg +3dgt)
±(4.0%rdg +5dgt)

• Over load pro tecti on: use t he fuse [ F 250mA /1KV]

To avoid ha rms to yo u or dama ge to the
meter from el ectri c shock . Pleas e do not
attempt to me asure v oltag e highe r than
DC 1000V/AC 7 00Vrms a lthou gh read ings
may be obtain ed.

5.1 DC & AC Voltage Measureme nt

5. Measurement Operation

The DC voltag e range s are 200 .0mV, 2.000V, 20.00 V ,

200.0V and 10 00V; an d then. The AC v oltag e range s
are 200.0mV,2.00 0V, 20. 00V, 20 0.0V an d 750.0 V.
To measure DC/A C volta ge:

1. Insert the r ed test l ead int o the “VΩ ” input t ermin al
and th e black t est lea d into th e COM ter minal .

2. First time , Defau lt mode i s DC meas ureme nt mode ,
you ca n selec t the AC vol tage mo de by 'FU NC“ key.

3. Set the rota ry swit ch to pro per DC/ AC mV or V ra nge.

4. Connect th e test le ad acro ss with t he obje ct bein g
meas ured. The m easur ed valu e will be s how on th e
LCD display.

6. If th e “OL” sy mbol is d ispla yed on th e LCD, yo u
must b e set the r otary s witch t o the hig her ran ge.

Note:
In the rang of 20 0mV in DC /AC and 2 V AC, even i n the

absence of in put or co nnect ivity t est lea der, the re also
have someth ing dis play on L CD. in th is case ,
short-cir cuit "V " and "CO M", so th at LCD di splay
back to zero.

12 13

To avoid da mage to t he Mete r or to the
equipment u nder te st, dis conne ct powe r
and di schar ge all hi gh-vo ltage c apaci tors
before resi stanc e measu remen t.

5.2 Resistance Measur eme nt

The resista nce ran ge are: 200Ω, 2.000 kΩ,20 .00kΩ ,

200.0kΩ,2 .000M Ω,20. 00MΩ.

To measure resi stanc e, conn ect the m eter as f ollow s:

1. Insert the r ed test l ead int o the ”VΩ ” termi nal and
the bl ack tes t lead in to the CO M termi nal.

2. Set the rota ry swit ch to pro per res istan ce rang e.
Connect the t est lea d acros s with th e objec t being
measured. The m easur ed valu e will be d ispla y
on the L CD.

Note:

The test lead c an add 0. 1Ω to 0.2 Ω of erro r to
resistanc e measu remen t. To obtain prec ision r eadin g
in low-resi stanc e measu remen t, that i s the ran ge of

200.0Ω, sho rt the in put ter minal b efore m easur ing. In
this time, th e conta ct resi stanc e displ ayed on t he LCD.

You can subtract the c ontac t resis tance v alue fr om
the measure d value .

For high-re sista nce mea surem ent (>1 0MΩ), i t is
normal taki ng seve ral sec ond to ob tain st able re ading .

The LCD displ ay “OL” i ndica ting op en-ci rcuit f or the
tested resi stor or t he resi stor va lue is hi gher th an the
maximum ran ge of the m eter.

To avoid da mage to t he Mete r or to the
equipment u nder te st, dis conne ct powe r
and di schar ge all hi gh-vo ltage c apaci tors
before Diod e/Con tinui ty chec k.

5.3 Diode/Continuity check

To avoid da mage to t he Mete r or to the
equipment u nder te st, dis conne ct powe r
and di schar ge all hi gh-vo ltage c apaci tors
before Diod e/Con tinui ty chec k.

1. insert the r ed test l ead int o the “VΩ ” termi nal and t he
black test le ad into t he COM te rmina l.

2. Set the rota ry swit ch to Ω pos ition .

2. For forwar d volta ge drop r eadin g on any
semi condu ctor co mpone nt, pla ce the re d test le ad
on the c ompon ent ano de and pl ace the b lack te st
lead on the com ponen t catho de. The mea sured
value show on t he LCD.

3. Select the c ontin uity ch eck mod e by the “F UNC” ke y.
The buzzer may be s ound if t he resi stanc e of a circ uit
under test is l ess tha n 30Ω.

5.3 Capacitance Measu rem ent

1. insert the r ed test l ead int o the “VΩ ” termi nal and t he
black test le ad into t he COM te rmina l.

2. Set the rota ry swit ch to Ω pos ition .

2. For forwar d volta ge drop r eadin g on any
semi condu ctor co mpone nt, pla ce the re d test le ad
on the c ompon ent ano de and pl ace the b lack te st
lead on the com ponen t catho de. The mea sured
value show on t he LCD.

3. Select the c ontin uity ch eck mod e by the “F UNC” ke y.
The buzzer may be s ound if t he resi stanc e of a circ uit
under test is l ess tha n 30Ω.

14 15

5.5 Capacitance Measu rem ent

Warning

To avoid damaging mete r or devi ce to be me asure d,
before cont inuit y tests , turn off al l circu its to be
tested and di schar ge all ca pacit ors.
The capacit ance me asuri ng rang e of this m eter:

2.000nF, 20.0 0nF, 200. 0nF, 2.00 0uF and 2 00.0u F.

Method of mea surin g capac itanc e:

1. Rotate swi tch to th e appro priat e posit ion.

2. Connect bl ack and r ed test p robe to C OM inpu t socke t
and V input soc ket, re spect ively. (You can als o use
the de dicat ed mult ifunc tion te st hold er to mea sure
capacitan ce).

3. Measure th e two lea ds of the c apaci tor to be t ested
with o ther tw o ends of t est pro bes and r ead the
measured va lue fro m LCD dis play.

Note:
When measur ing bul k capac itors w ith thi s meter,
readings wi ll be sta blize e after a f ew seco nds.
When measur ing the s mall ca pacit or with l ess tha n 20nF,
the distrib uted ca pacit ance (d ispla yed bas e numbe r)
of the meter an d wire sh ould be s ubtra cted.

5.6 Transistor Measure men t

Warning

Do not apply an y RMS vol tage hi gher th an 250V D C
or AC between co mmon en d and hFE e nd.
This preven ts elec trica l shock a nd/or m eter da mage.

Method of mea surin g trans istor :

1. Rotate the s witch t o hFE pos ition .

2. Plug multi -func tion so cket wi th corr ect pol arity
(the “ +” end of m ulti- funct ion soc ket is co nnect ed with
hFE en d, “COM ” end is co nnect ed with c ommon e nd).

3. Determin e that th e trans istor i s NPN or PN P ty pe,
then i nsert t hree pi ns of tra nsist or, e.b. c, to the
corr espon ding ho les of de dicat ed mult i-fun ction al
sock et.

4. Read hFE app roxim ation o f trans istor t o be meas ured
from L CD disp lay.

16 17

5.7 Frequency Measure men t

Warning

Do not measur e the fre quenc y of RMS vo ltage
higher than 2 50V DC or AC . Th is prev ents el ectri cal
shock and/o r meter d amage .

Method of mea surin g frequ ency:

1. Rotate swi tch to 20 KHZ pos ition .

2. Connect bl ack and r ed test p robe to C OM inpu t socke t
and HZ input so cket, r espec tivel y.

3. Measure th e frequ ency va lue of ci rcuit t o be test ed
with o ther tw o ends of t est pro bes.

4. Read the mea sured f reque ncy val ue from L CD disp lay.

Note:
Do not input th e volta ge over 1 0V RMS, a s accur acy of
readings ca nnot be g uaran teed.

5.8 Current Measureme nt

Warning

To avoid damage to meter o r devic e, befo re
measuring c urren t, plea se chec k the met er's fu se.
When measur ing, us e corre ct inpu t socke t, func tion
selection a nd meas uring r ange.
When the circ uit vol tage is o ver 250 V, do not a ttemp t
to measure cu rrent o n the cir cuit.
When the test p robe is i nsert ed to the c urren t input
socket, don 't conn ect the o ther en d of the te st prob e
with any circ uit in pa ralle l.
DC measurin g range o f meter :

2.000mA, 20 .00mA , 200.0 mA and 10. 00A;
AC measurin g range : 200.0 0mA and 10 A.

Method of mea surin g curre nt:

1. Turn off the powe r suppl y and dis charg e all hig h
voltage cap acito rs on the c ircui t to be tes ted.

2. Rotate swi tch to th e appro priat e posit ion.

3. Connect th e black t est pro be to the C OM inpu t socke t.
If the c urren t to be tes ted is lo wer tha n 200mA , conne ct
the re d test pr obe to th e mA input s ocket . If the
measured cu rrent i s betwe en the ra nge of 20 0mA~1 0A,
the re d test pr obe sho uld be co nnect ed to 10A in put
sock et.

4. Turn off the circ uit to be t ested . Conne ct the bl ack tes t
probe to the lo w volta ge end of d iscon necte d circu it to
be tes ted and t he red te st prob e is conn ected t o the
othe r end (hi gh volt age) of d iscon necte d circu it.

5. Connect th e power s upply t o the cir cuit, t hen rea d the
LCD display. If th e displ ay show s only “O L”, it me ans
that t he inpu t is out of t he sele cted in put ran ge.
Please rota te the sw itch to a h igher m easur ing ran ge.

6. Turn off the powe r to the ci rcuit t ested . Disch arge al l
the ca pacit ors, re move th e test pr obes fr om the me ter
and restore t he circ uit to th e origi nal sta te.

Note:

1. When measu ring cu rrent , the met er shou ld be
connected i n serie s, inst ead of in p arall el, to av oid the
mete r damag e and ris king pe rsona l safet y.

2. Lengthy me asure ments o f large c urren ts (>10 A) will
affect t he disp lay acc uracy o f the met er. Stan dard te st
time c annot b e over 10 s econd s in any 3 mi nute pe riod.

3. During DC me asure ment, i f the tes t probe s are
connected i n rever sal ord er to the c ircui t, the di splay
will become n egati ve, but t he meas ureme nt accu racy
of the m eter wi ll not be a ff ected .

18 19

6.1 Battery Replaceme nt

6. Maintenance

5.9 Temperature Measurement

Warning

Do not input an y volta ge high er than 1 2V DC or AC
RMS within th e tempe ratur e measu ring ra nge, to
avoid damag e to the me ter.

Method of mea surin g tempe ratur e:

The MS3203 mu ltifu nctio n socke t with K- type
temperatu re prob e is requ ired fo r measu ring te mpera ture.

1. Rotate the k nob to th e TE MP positi on. The LCD w ill
display “OL ” and tem perat ure uni t °C.

2. When inser ting th e multi funct ion soc ket, in sert “C OM”
and “V” leads o f the soc ket in th e comm en d and
curr ent MA jac ket res pecti vely.

3. Then insert th e tempe ratur e probe i nto the s ide
temp eratu re jack et of the m ultif uncti on sock et.
Note t he pola rity of t he atta chmen t. The LCD wi ll
display the t emper ature o f the cur rent en viron ment.

4. The other end of t he temp eratu re prob e
(the t emper ature s ensor ) is put in to the ob ject to b e
test ed. The LCD w ill dis play th e tempe ratur e at the
location of t he curr ent sen sor.

5. Press the “F UNC” ke y to conv ert the m easur ed valu e
to °F, or se t the tem perat ure uni t to °F fir st befo re
measuring .

When the symb ol show s on the di splay d uring

use of the mete r, you mus t repla ce the ba tteri es, to
avoid affecti ng the no rmal us e of the me ter.

Method of rep lacin g batte ries:

1. Disconne ct the te st wire . Switc h off the pow er.

2. Open the bat tery co ver on th e rear of t he case w ith
the sc rewdr iver, an d remov e the bat terie s.

3. Install ba tteri es with s ame spe cific ation ,
and secure th e cover.

6.2 Fuse Replacement

Steps for rep lacin g fuse:

1. First remo ve the te st wire , and swi tch off the m eter.

2. Open the bat tery co ver on th e rear co ver wit h the
scre wdriv er, and re move th e damag ed fuse .

3. Install a fu se with s ame spe cific ation , put the b atter y
cove r in plac e again , and tig hten th e screw s.

6.3 Cleaning

Please wipe t he surf ace of th e meter w ith the s oft clo th
and mild dete rgent , if nece ssary. Do no t use org anic
solvents as t hey wil l corro sion th e meter 's case .

HYS006665