HowtoUsethisModule.......................................................................................................

Introduction..........................................................................................................................
TechnicalTerms....................................................................................................................
LearningOutcome#1..........................................................................................................1
InformationSheet#11.......................................................................................................2
OperationSheet#11..........................................................................................................6
LearningOutcome#2..........................................................................................................8
InformationSheet#2.1.......................................................................................................9
ActivitySheet#2.1............................................................................................................10
LearningOutcome#3........................................................................................................13
JobSheet

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Welcome to the Module Terminating and Connecting Electrical Wiring and

Electronic Circuits. This module contains training materials and activities for you to
complete.
The unit of competency Terminate and Connect Electrical Wiring and Electronic
Circuits contains knowledge, skills and attitudes required for a Computer Hardware
Servicing NC II course.
You are required to go through a series of learning activities in order to complete
each of the learning outcomes of the module. In each learning outcome there are Job
Sheets, and Activity Sheets. Follow these activities on your own and answer the Self-Check
at the end of each learning activity.
If you have questions, do not hesitate to ask your teacher for assistance.
Recognition of Prior Learning (RPL)
You may already have some of the knowledge and skills covered in this module
because you have:
o been working for some time
o completed training in this area.
If you can demonstrate to your teacher that you are competent in a particular skill or
skills, talk to him/her about having them formally recognized so you do not have to do the
same training again. If you have a qualification or Certificate of Competency from previous
trainings show it to your teacher. If the skills you acquired are still current and relevant to
this module, they may become part of the evidence you can present for RPL. If you are not
sure about the currency of your skills, discuss it with your teacher.
After completing this module ask your teacher to assess your competency. Result of
your assessment will be recorded in your competency profile. All the learning activities are
designed for you to complete at your own pace.
Inside this module you will find the activities for you to complete followed by
relevant information sheets for each learning outcome. Each learning outcome may have
more than one learning activity.

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Program/Course

Computer Hardware Servicing NC II

Unit of Competency

Terminate and Connect Electrical Wiring and Electronic

Circuits

Module

Terminating and Connecting Electrical Wiring and

Electronic Circuits

INTRODUCTION

ThismodulecontainsinformationandsuggestedlearningactivitiesonComputerHardware
Servicing NC II. It includes the following competencies: plan and prepare for termination/
connections of electrical wiring/electronic circuits, terminate/connect electrical wiring/electronic
circuits,andtesttermination/connectionsofelectricalwiring/electroniccircuits.
Itconsistsofthree(3)learningoutcomes.Eachlearningoutcomecontainslearningactivities
supportedbyeachinstructionalsheet.Uponcompletionofthismodule,reporttoyourteacherto
assess your achievement of knowledge and skills requirement of this module. If you pass the
assessment,youwillbegivenacertificateofcompletion.

SUMMARYOFLEARNINGOUTCOMES:

Uponcompletionofthemoduleyoushouldbeableto:

LO1.

Planandprepareforterminationandconnectionofelectricalwiringandelectroniccircuits.

LO2.

Terminateandconnectelectricalwiringandelectroniccircuits.

LO3.

TestTerminationandconnectionofelectricalwiringand/electroniccircuit.

REFERENCES:

1. Agpaoa,Feliciano,InteriorandExteriorWiringTroubleshooting,NationalbooksStore,1991
2. Enriquez, Michael, Simple Electronics (Basic) Fully Illustrated, Antonio M. Andes Sr.
ElectronicsBookSeries
3. www.electronicslab.com
4. www.wikipedia.com

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Voltage

The measure of the push on each electron which makes the electron
move. The term potential difference and voltage are often used
interchangeably to mean the push, thus, you may see the term
electromotive force (EMF) or just the word potential to describe the
electronpushincertaininstances.

Current

Theflowofelectronsinthecircuit.

Resistance

Theoppositiontocurrentflow.

Power

Therateofdoingwork.

Resistor

Adevicedesignedintentionallytohaveadefiniteamountof

resistance

Capacitor

Termination

Adevicethatstoreselectricalenergy.

- The point where a line, channel or circuit ends.

OHS

OccupationalHealthandSafety

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Program/Course

ComputerHardwareServicingNCII

UnitofCompetency

: TerminateandConnectElectricalWiringandElectronic
Circuits

Module#3

: TerminatingandConnectingElectricalWiringandElectronic
Circuits

LearningOutcome1:PlanandPrepareforTerminationandConnectionofElectrical
WiringandElectronicCircuits

AssessmentCriteria:

1.
2.
3.
4.

Materialsarecheckedaccordingtospecificationsandtask.
Appropriatetoolsandequipmentareselectedaccordingtotaskrequirements.
TaskisplannedtoensurethatOHSguidelinesandproceduresarefollowed.
Electricalwiringelectronicscircuitsareappropriatelypreparedforconnection/
terminationinaccordancewithinstructionsandworksiteprocedure.

References:
1. Agpaoa, Feliciano, Interior and Exterior Wiring Troubleshooting, National books
Store,1991
2. Enriquez,Michael,SimpleElectronics(Basic)FullyIllustrated,AntonioM.AndesSr.
ElectronicsBookSeries
3. Cardenas, Elpidio, Fundamentals and Elements of Electricity, National Book Store,
1991
4. www.wikipedia.com

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DirectCurrentandAlternatingCurrent
DirectCurrentorDCisthefirsttypeofcurrentbecauseitwaseasytoproduce.Thistypeof
currentalwaysflowsinonedirection.OneofthedisadvantagesofusingDCistheexcessive
voltagedropandpowerlossinthepowerlinesinalongdistancetransmission.Batteriesare
commonsourcesofdirectcurrent.

AlternatingCurrentorACisthesolutiontotheproblemofDC.ACallowstheflowofcurrent
intwodirections.Today,itispossibletostepupelectricity,apowerstation,transmititto
anydistantplaceandstepitdowntoforconsumption.Atransformeristhedeviceusedfor
steppingup or steppingdown AC voltage. Common sources of AC are found in our AC
outlet(Typically,220volts,inthePhilippines).

ACandDCWaveForm

OHMSLAWANDPOWERLAW

Ohms law states that, for a constant current, the current in a circuit is directly
proportional to the total voltage acting in the circuit and inversely proportional to the
totalresistanceofthecircuit.

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ThelawmaybeexpressedbythefollowingequationifthecurrentIisinamperes,EMFEis
involts,andtheresistanceRisinohms.

The relationship of the foregoing three variables was discovered by Georg Simon Ohm,
who theorized that current is in direct proportion to resistance. The relationship is
explainedalgebraically,usingthisformula:
where:

R = E/I

E=IxR

I = E/R

Resistance

Voltage

Current

E EMF in Volts
R Resistance
I Current in Amperes

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A. PracticeProblems:

1.

Required

I=?
E=25V

R=25

G. I

H. P

2.

I=9A
E=?

Required

R=72

E. E

F. P

Required

I=25A
E=?

P=100W

C. R

D. E

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3.

I=4.5A
E=?

Required

P=350W

A. E

B. R

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ASimplecircuitcontainstheminimumthingsneededtohaveafunctioningelectric
circuit.Asimplecircuitrequiresthefollowing:

AC/DCsource
EquipmentthatwilloperateoneitheranACorDCpowersource
BatteryAdcvoltagesourcecontainingtwoormorecellsthatconvert
chemicalenergytoelectricalenergy.
Cell Single unit used to convert chemical energy into a DC electrical
voltage.
FUSE
Onceyoudesignasimplecircuitonelectronics,it
isimportanttoincludea
fuse in the primary or
secondaryofatransformer.

Fuse is a safety device used to protect an

electrical circuit from the effect of excessive
current. Its essential component is usually a
strip of metal that will melt at a given
temperature.Afuseissodesignedthatthestripofmetalcaneasilybe
placed in the electric circuit. If the current in the circuit exceed a
predeterminedvalue,thefusiblemetalwillmeltandthusbreak,oropen
thecircuit.
A fuse is usually rated in Amperes, which represent the maximum
continuouscurrentitcouldhandlewithoutblowing.
The most popular type of fuse in Electronics is 3AG type. This code
describes the case size and material where G indicates a glass
materialsandAindicatesthatintendedforautomotiveapplication.A
3AGfusemeasuresapproximately32mmx6mm.

WiresandCable
Awireisasingleslenderrodorfilamentof
drawnmetal.Thisdefinitionrestrictstheterm
to what would ordinarily be understood as
solidwire.Thewordslenderisusedbecause
the length of a wire is usually large when
comparedtoitsdiameter.Ifawireiscovered
with insulation, It is an insulated wire.
Although the term wire properly refers to
themetal,italsoincludestheinsulation.
A conductor is a wire suitable for carrying
anelectriccurrent.

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A stranded conductor is a conductor composed of a group of wire or any

combination of group of wires. The wires in a stranded conductor are usually
twistedtogetherandnotinsulatedfromeachother.

A cable is either a stranded conductor (singleconductor cable) or a

combination of conductors insulated from one another (multipleconductor
cable).Thetermcableisageneraloneandusuallyappliesonlytothelarge
sizes of conductor. A small cable is more often called a stranded wire or cord
(suchasthatusedforanironoralampcord).Cablesmaybebareorinsulated.
Insulatedcablesmaybesheathed(covered)withlead,orprotectivearmor.

Switchanditsfunction
Switch is adevice used to break an electric current or transfer it to another
conductor.Switchesarecommonlyusedtoopenorcloseacircuit.Closedis
the ON position, while open is OFF position. Normally, switch is installed in
serieswiththelinecarryingcurrentfrom
thepowersourcetotheload.
A switch is a mechanical device used to
connect and disconnect a circuit at will.
Switches cover a wide range of types,
from subminiature up to industrial plant
switching megawatts of power on high
voltagedistributionlines.
Switch is a manually operated device
capable of making, breaking, or changing
the connection in an electronics or
electrical circuit. A switch connected in
series with one of the connecting wires of simple circuit affords a means of
controllingthecurrentinthecircuit.
Switchfunction
o When the switch is closed, the electron finds an interrupted path in the
circuit.
o OpenistheOFFpositionoftheswitch,whileclosedistheONposition.
o Whentheswitchisopened,thecurrentdeliveredbythepowersupplyis
normallyinsufficienttojumptheswitchgapintheformofanarcandthe
electronflowinthecircuitisblocked.

Load a source drives a load. Whatever component or piece of equipment is

connectedtoasourceanddrawscurrentfromasourceisaloadonthatsource.
o Thefollowingareexamplesbutnotlimitedto:
Bulb
Appliances

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I.

ClassificationsofElectronicComponent
A. Passive devices A Passive Device is one that contributes no power gain
(amplification)toacircuitorsystem.Ithasnocontrolactionanddoesnot
requireanyinputotherthanasignaltoperformitsfunction.Inotherwords,
"A component with no brains!" Examples are Resistors, Capacitors and
Inductors.
RESISTOR

Thisisthemostcommoncomponentinelectronics.
It is used mainly to control current and voltage
withinthecircuit.Youcanidentifyasimpleresistor
by its simple cigar shape with a wire lead coming
out of each end. It uses a system of color coded
bands to identify the value of the component
(measuredinOhms)

Capacitors,or"caps",varyinsizeandshapefrom
asmallsurfacemountmodeluptoahugeelectric
motorcapthesizeofpaintcan.Whateverthesize
or shape, the purpose is the same. It stores
electricalenergyintheformofelectrostaticcharge.

It is charged with a magnetic field and when that

field collapses it produces current in the opposite
direction.InductorsareusedinAlternatingCurrent
circuitstoopposechangesintheexistingcurrent.

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B. Active Devices are components that are capable of controlling voltages or

currents and can create a switching action in the circuit. In other words,
"Devices with smarts!" Examples are Diodes, Transistors and Integrated
circuits.

Diodes are basically a oneway valve for electrical

current. They let it flow in one direction (from
positivetonegative)andnotintheotherdirection.
Mostdiodesaresimilarinappearancetoaresistor
andwillhaveapaintedlineononeendshowingthe
direction or flow (white side is negative). If the
negative side is on the negative end of the circuit,
current will flow. If the negative is on the positive
sideofthecircuitnocurrentwillflow.

LEDsare simply diodes thatemit light of one form

or another. They are used as indicator devices.
Example: LED lit equals machine on. They come in
several sizes and colors. Some even emit Infrared
Lightwhichcannotbeseenbythehumaneye.

The transistor is possibly the most important

invention of this decade. It performs two basic
functions. 1) It acts as a switch turning current on
and off. 2) It acts as an amplifier. This makes an
output signal that is a magnified version of the
inputsignal.
Integrated Circuits, or ICs, are complex circuits
inside one simple package. Silicon and metals are
used to simulate resistors, capacitors, transistors,
etc.Itisaspacesavingmiracle.

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ELECTRONICSCHEMATICSYMBOLS

Wiresandconnections
Component

CircuitSymbol

FunctionofComponent

Wire

Topasscurrentveryeasilyfromonepartof
acircuittoanother.

Wiresjoined

A'blob'shouldbedrawnwherewiresare
connected(joined),butitissometimes
omitted.Wiresconnectedat'crossroads'
shouldbestaggeredslightlytoformtwoT
junctions,asshownontheright.

Wiresnotjoined

Incomplexdiagramsitisoftennecessaryto
drawwirescrossingeventhoughtheyare
notconnected.Ipreferthe'bridge'symbol
shownontherightbecausethesimple
crossingontheleftmaybemisreadasa
jointwhereyouhaveforgottentoadda
'blob'!

PowerSupplies/Source
Component

CircuitSymbol

FunctionofComponent

Cell

Supplieselectricalenergy.
Thelargerterminal(ontheleft)ispositive(+).
Asinglecellisoftencalledabattery,but
strictlyabatteryistwoormorecellsjoined
together.

Battery

Supplieselectricalenergy.Abatteryismore
thanonecell.
Thelargerterminal(ontheleft)ispositive(+).

DCsupply

Supplieselectricalenergy.
DC=DirectCurrent,alwaysflowinginone
direction.

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ACsupply

Supplieselectricalenergy.
AC=AlternatingCurrent,continuallychanging
direction.

Fuse

Asafetydevicewhichwill'blow'(melt)ifthe
currentflowingthroughitexceedsaspecified
value.

Transformer

Earth
(Ground)

Twocoilsofwirelinkedbyanironcore.
Transformersareusedtostepup(increase)
andstepdown(decrease)ACvoltages.Energy
istransferredbetweenthecoilsbythe
magneticfieldinthecore.Thereisnoelectrical
connectionbetweenthecoils.
Aconnectiontoearth.Formanyelectronic
circuitsthisisthe0V(zerovolts)ofthepower
supply,butformainselectricityandsome
radiocircuitsitreallymeanstheearth.Itisalso
knownasground.

OutputDevices/Loads:Lamps,Heater,Motor
Component

CircuitSymbol

FunctionofComponent

Lamp(lighting)

Atransducerwhichconvertselectrical
energytolight.Thissymbolisusedfora
lampprovidingillumination,forexamplea
carheadlamportorchbulb.

Lamp(indicator)

Atransducerwhichconvertselectrical
energytolight.Thissymbolisusedfora
lampwhichisanindicator,forexamplea
warninglightonacardashboard.

Heater

Atransducerwhichconvertselectrical
energytoheat.

Motor

Atransducerwhichconvertselectrical
energytokineticenergy(motion).

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Atransducerwhichconvertselectrical
energytosound.

Bell

Atransducerwhichconvertselectrical
energytosound.

Buzzer

Inductor
(Coil,Solenoid)

Acoilofwirewhichcreatesamagneticfield
whencurrentpassesthroughit.Itmayhave
anironcoreinsidethecoil.Itcanbeused
asatransducerconvertingelectricalenergy
tomechanicalenergybypullingon
something.

Switches
Component
PushSwitch
(pushto
make)

CircuitSymbol

FunctionofComponent
Apushswitchallowscurrenttoflowonlywhenthe
buttonispressed.Thisistheswitchusedtooperatea
doorbell.

PushtoBreak
Switch

Thistypeofpushswitchisnormallyclosed(on);itis
open(off)onlywhenthebuttonispressed.

OnOffSwitch
(SPST)

SPST=SinglePole,SingleThrow.
Anonoffswitchallowscurrenttoflowonlywhenit
isintheclosed(on)position.

2waySwitch
(SPDT)

SPDT=SinglePole,DoubleThrow.
A2waychangeoverswitchdirectstheflowof
currenttooneoftworoutesaccordingtoitsposition.
SomeSPDTswitcheshaveacentraloffpositionand
aredescribedas'onoffon'.

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DPST=DoublePole,SingleThrow.
Adualonoffswitchwhichisoftenusedtoswitch
mainselectricitybecauseitcanisolateboththelive
andneutralconnections.

DualOnOff
Switch
(DPST)

Completethetablebelow:

A. Identifyeachofthesesymbols:
COMPONENTS

SYMBOLS

1.

2.

3.

4.

5.

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B. Identifythefollowingbasicelectroniccomponents

COMPONENT

FIGURE

1.

2.

3.

4.

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Asimplecircuitcontainstheminimumthingsneededtohaveafunctioningelectric
circuit

SourceadeviceusedtosupplyACorDCvoltage
Consuminganydevicethatconsumesvoltage,whatevercomponentorpieceof
equipmentthatisconnectedtoasourceanddrawscurrentfromasourceisa
loadonthatsource.
Controlling any device having two states, on (closed) or off (open). Ideally
havingzeroimpedancewhenclosedandinfiniteimpedancewhenopen.
Protectinga component used to open the circuit when current exceeds a
predeterminedmaximumvalue.
Connecting a material that conducts electric current very well and used to
connectacompletepathforcurrent.

CONTROLLING

source

CONSUMING

Connecting device

ProcedureinCircuitDesigning
1. Prepareallthetoolsandmaterialsneeded.
2. Byusingschematicsymbol,makeasimplecircuitwiththefollowing:
a. load
b. consumingdevice
c. protectingdevice
d. consumingdevice
e. connectingdevice
3. Make sure that the circuit has the following requirement that a
simplecircuitmusthave:
a. Asourceofelectricalpotentialdifferenceorvoltage.
b. A conductive path which would allow for the
movementofcharges.
c. Anelectricalresistancewhichislooselydefinedasany
objectthatuseselectricitytodowork.

4. Test the designed circuit by comparing it with the sample circuit

producedbyyourteacher.

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A.Fillintheblankswithwhatisreferredtobyeachofthefollowing.

1._______________________ Interconnection of components which provides an

electricalpathbetweentwoormorecomponents.
2._______________________ Atypeofcircuitinwhichtheflowofcurrentiscutoff.
3._______________________ Acircuitinwhichthecomponentsareconnectedfrom
end to end so that the current has only one path to
followthroughthecircuit.
4._______________________ A circuit where there is more than one path for the
currenttoflowthrough.
5._______________________ AdeviceusedtosupplyACorDCvoltage.
6._______________________ Anydevicehavingtwostates,ONorOFF.
7._______________________ Asafetydeviceusedtoprotectanelectricalcircuit
fromtheeffectofexcessivecurrent.
8._______________________ pathwayforcarryinganelectricalcurrent.
9._______________________ Components or pieces of equipment connected to a
source whichdrawscurrentfromasource.
10._______________________ ADCvoltagesourcecontainingtwoormorecellsthat
convertchemicalenergytoelectricalenergy.

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A.

InitialStepsinUsingAnalogMultitester

1. Connectthetestprobetotheappropriatejack.
Theredtestprobetothepositive(+)jackandtheblacktothecommon()jack.

COM

+POS

(Black)

(Red)

2. Checkifthepointerrestsexactlyattheinfinitezeropositioninohmmeterrange.

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3. Checktheprobesiftheyareincondition.(Ohmmetercalibration)
a. SettheMultitestertocorrespondingselectorresistancerange.
b. Shortthetwotestprobesleadtogether.

ZeroOhm
Adjustment
knob

Note:

Thepointershoulddeflect
towardszeroohmreading

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Zero
ohm

As indicated, the pointer rests out of

the range of ohmmeter scale. Adjust
the ohm adjustment counter
clockwise until the pointer rests O
ohm reading.

Adjust the ohm adjustment if the

pointer could not rest exactly at O

ohm reading.

B.

ResistanceMeasurements
1. AlwaysdotheInitialStepsinUsingAnalogMultitester.
2. In testing resistors, capacitors, diodes etc. do not touch both test probe lead,
because our body also has resistance that could affect the reading value of the
electroniccomponentswearetesting.
3. If you do not know the value of the resistor to be measured, find the ohmmeter
selectorsettinguntilyouhaveaclearreadingintheohmmeterscale.

OhmmeterScale

(FrominfinitetoZero)

InfiniteResistance
openresistorOpen
connectionor

Ohm
Adjustment

OhmmeterSelector
Range
(x1,x10,x1K,x10K
ohms)

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4. Selectthedesiredresistancerangescalewithselectorswitch.

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Testinga55Kohmresistance

Range:x10Kohm

Thepointerstopsat5.5inx10K
rangeonselectorswitch

Testinga55Kohmresistance

Range:x1Kohm

The setting (x1K in 56K Ohm resistor) is not an

advisablesettingintesting55Kohmsresistance.Because,
the pointer stops somewhere in 50. You cannot clearly
readtheresistancevalue,unlikeinx10Kohmsetting.

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