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    EE201 Semiconductor DeviceEE201 Semiconductor Device 11

    TOPIC 2

    ~DIODES~

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    Doa mula kelasDoa mula kelas

    Ya Tuhan, lapangkanlah dadaku, mudahkanlahYa Tuhan, lapangkanlah dadaku, mudahkanlah

    segala urusanku, dan lepaskanlah kekakuan lidahku,segala urusanku, dan lepaskanlah kekakuan lidahku,

    agar mereka mengerti perkataanku.agar mereka mengerti perkataanku.(Thaha: 27)(Thaha: 27)

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    By the end of this class, studentsBy the end of this class, students

    should be able to:should be able to:~~ Understand the characteristics of diode and diode as a semiconductorUnderstand the characteristics of diode and diode as a semiconductor

    device.device.

    ~~ Determine !" characteristic curve for silicon diode and e#$lain:Determine !" characteristic curve for silicon diode and e#$lain:

    a. %nee "olta&e (Threshold volta&e )a. %nee "olta&e (Threshold volta&e )

    b. 'orard current (in milli m$ere scale)b. 'orard current (in milli m$ere scale)

    c. *everse current (in microm$ere scale)c. *everse current (in microm$ere scale)

    d. Brea+don volta&ed. Brea+don volta&e

    e. Burnin& level (hen d, "d e#ceeds ma#)e. Burnin& level (hen d, "d e#ceeds ma#)

    ~~ %no diode a$$lications as rectifiers.%no diode a$$lications as rectifiers.

    ~~ Diode as cli$$er and clam$er circuits.Diode as cli$$er and clam$er circuits.

    ~~ Understand other ty$es of diode:Understand other ty$es of diode:

    a. -ener diodea. -ener diode

    b. i&ht emittin& diode (/D)b. i&ht emittin& diode (/D)

    c. hotodiodec. hotodiode

    d. aser dioded. aser diode

    EE201-semiconductor deviceEE201-semiconductor device 33

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    DiodesDiodes

    ~~ n effect, diodes act li+e a fla$$er valven effect, diodes act li+e a fla$$er valve ote: this is the sim$lest $ossible model ofote: this is the sim$lest $ossible model of

    a diodea diode

    EE201 Semiconductor DeviceEE201 Semiconductor Device 55

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    DiodesDiodes

    ~ 'or the fla$$er valve, a small $ositive~ 'or the fla$$er valve, a small $ositive$ressure is reuired to o$en.$ressure is reuired to o$en.

    ~ i+eise, for a diode, a small $ositive~ i+eise, for a diode, a small $ositive

    volta&e is reuired to turn it on. Thisvolta&e is reuired to turn it on. This

    volta&e is li+e the volta&e reuired tovolta&e is li+e the volta&e reuired to

    $oer some electrical device. t is used u$$oer some electrical device. t is used u$

    turnin& the device on so the volta&es atturnin& the device on so the volta&es at

    the to ends of the diode ill differ.the to ends of the diode ill differ. The volta&e reuired to turn on a diode isThe volta&e reuired to turn on a diode is

    ty$ically around 8.9!8. volt for a standardty$ically around 8.9!8. volt for a standard

    silicon diode and a fe volts for a li&ht emittin&silicon diode and a fe volts for a li&ht emittin&

    diode (/D)diode (/D)EE201 Semiconductor DeviceEE201 Semiconductor Device 66

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    t the ;unction, free electrons from the !ty$e

    material fill holes from the !ty$e material. This

    creates an insulatin& layer in the middle of the

    diode called the de$letion

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    EE201 Semiconductor DeviceEE201 Semiconductor Device 88

    DIODE-FORWARD BIAS

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    EE201 Semiconductor DeviceEE201 Semiconductor Device99

    DIODE-REVERSE BIAS

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    Diode !" 5haracteristicDiode !" 5haracteristic~ 'or ideal diode, current flos only one ay~ 'or ideal diode, current flos only one ay

    ~ *eal diode is close to ideal~ *eal diode is close to ideal

    EE201 Semiconductor DeviceEE201 Semiconductor Device 1010

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    Diode !" 5haracteristicDiode !" 5haracteristic

    EE201 Semiconductor DeviceEE201 Semiconductor Device 1111

    'orard current'orard current == current flo hen forard bias volta&e arecurrent flo hen forard bias volta&e are&iven. (in milim$ere scale)&iven. (in milim$ere scale)

    *everse current*everse current ==small lea+a&e current, flo hen reverse biassmall lea+a&e current, flo hen reverse bias

    volta&e (in microm$ere scale (volta&e (in microm$ere scale (>>))))

    %nee "olta&e%nee "olta&e == threshold volta&e.(0i!8.7", ?e! [email protected]"). "olta&ethreshold volta&e.(0i!8.7", ?e! [email protected]"). "olta&e

    that current flo immediately.that current flo immediately.Brea+don volta&eBrea+don volta&e == volta&e that reverse current flo immediately.volta&e that reverse current flo immediately.

    ea+a&e 5urrentea+a&e 5urrent == Ahen a diode is reverse biased, a very smallAhen a diode is reverse biased, a very small

    amount of current can and does &o in reverseamount of current can and does &o in reverse directiondirection

    (i.e.o$$osite to conventional direction)(i.e.o$$osite to conventional direction) &ivin& rise to lea+a&e&ivin& rise to lea+a&e

    current.current.Burnin& evelBurnin& evel !! Ahen Ahen dd and "and "dd e#ceed ma#imum, thee#ceed ma#imum, the

    com$onents ill burn.com$onents ill burn.

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    deal Diodedeal Diode 'orard bias'orard bias= diode as a close sitch (3)= diode as a close sitch (3)

    because no resistance and volta&e dro$.because no resistance and volta&e dro$.

    *everse bias*everse bias== diode as o$en sitch (3''), infinitydiode as o$en sitch (3''), infinity

    resistance.resistance.

    EE201 Semiconductor DeviceEE201 Semiconductor Device 1212

    *everse bias

    3$en sitch (3'')

    5athodenode

    'orard bias

    5lose sitch (3)

    5athodenode

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    1313

    DIODE APPLICATIONSDIODE APPLICATIONS

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    2-1 Half-Wave Rectiers

    DIODEDIODE ability to conduct current in one direction andability to conduct current in one direction andbloc+ current in other direction bloc+ current in other direction

    used in circuit calledused in circuit called */5T'/* (ac dc)

    rectifierrectifieris an electrical device thatis an electrical device that

    converts alternatin& current (5), hichconverts alternatin& current (5), hich

    $eriodically reverses direction, to direct current$eriodically reverses direction, to direct current

    (D5), hich is in only one direction, a $rocess(D5), hich is in only one direction, a $rocess+non as+non as rectification.rectification.

    11

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    The basic function of a DC power supply isto convert an AC voltage to a constant DCvoltage (AC DC)

    Either half or full-wave

    rectier convert ac inputto a pulsating dc voltage.

    Eliminates the uctuations- produce smooth dc voltage

    Maintains a constavoltage

    The basic DC power supply

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    ~~ The a$$lied a.c si&nal across the secondary indin& chan&eThe a$$lied a.c si&nal across the secondary indin& chan&e

    $olarities after each half !cycle of su$$ly a.c volta&e.$olarities after each half !cycle of su$$ly a.c volta&e.

    ~~ t the time of the $ositive half!cycle of su$$ly a.c volta&e,t the time of the $ositive half!cycle of su$$ly a.c volta&e,

    diode is in forard biased and it conduct current in the circuits.diode is in forard biased and it conduct current in the circuits.

    ~~ t the time of ne&ative half!cycle of in$ut a.c volta&e, diodet the time of ne&ative half!cycle of in$ut a.c volta&e, diodebecomes reverse biased and it does not conduct current in thebecomes reverse biased and it does not conduct current in the

    circuits.circuits.

    ~~ n this ay, current flos via the load at the time of $ositiven this ay, current flos via the load at the time of $ositive

    half!cycle of in$ut a.c volta&e only here as no conduct currenthalf!cycle of in$ut a.c volta&e only here as no conduct current

    throu&h the load at the time of ne&ative half!cycle in the samethrou&h the load at the time of ne&ative half!cycle in the samedirection is obtain across load for other ne#t cycle.direction is obtain across load for other ne#t cycle.

    ~~ But this out$ut is $ulsatin& d.c .But this out$ut is $ulsatin& d.c .

    EE201 Semiconductor DeviceEE201 Semiconductor Device 1616

    Half-Wave Rectier

    Operation

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    1!1!

    A half wave

    rectier(ideal) allowsconduction for only180 or half of aco!plete cycle""

    During rst one cycle#

    Vingoes positive $diode FB$ conductcurrent

    Vin goes negative $diode RB $ no

    current% 0& The output fre'uencyis the sa!e as the input(sa!e shape)"

    The averaevalue !DC or

    !A!"#

    deal diode

    !odel

    p

    AVG

    VV =

    $$ %easure on &c volt'eter

    The Half-Wave Rectier

    ac source load resistor

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    ractical Diode barrier potential of 0"*& (+i) ta,en into account"

    During -ve half%cycle &in!ust overco!e &potentialfor forward bias"

    Example 1: Calculate the peak o/p voltage, VExample 1: Calculate the peak o/p voltage, Vp(oup(out!t!

    The pea, o.p voltage# VVV inpoutp 7.0)()( =

    1"1"

    ()ect of the *arrier +otential onthe Half-Wave Rectier Output

    V

    VV

    VVV inpoutp

    30.4

    7.05

    7.0)()(

    =

    =

    =

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    1#1#

    Example ":

    +,etch the output V0 and deter!ine the output level v

    networ, in above gure"

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    2020

    ea,inversevoltage(&) is themaximumvoltageacross thediodewhen it isin reverse

    bias.

    The diode !ustbe capable of

    withstandingthis a!ount ofvoltage"

    )(inpVPIV=

    +ea, nverse !oltae .+!/

    Half Wave Rectier with

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    2121

    Transfor!ers are often used for voltagechange and isolation" The turns ratio, nof the pri!ary to secondary

    deter!ines the output versus the input.

    The advantages of transfor!er coupling# 1) allows the source voltage to be stepped

    up or down /) the ac source is electrically isolated fro!the rectier thus

    prevents shoc, haards in thesecondary circuit"to couple ac input

    to the rectier

    VVV poutp 7.0(sec))( =

    (sec)pVPIV=priN

    Nn sec=

    prinVV =sec

    Half-Wave Rectier withTransfor'er-Couple& nput

    !oltae

    If n1! "sec is #re$ter t%$n "&ri.

    If n'1! "sec is ess t%$n "&ri.

    If n1! "sec "&ri.

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    Example #:

    2222

    Deter!ine the pea, value of output voltage asshown in 2igure below"

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    2323

    Twice oup

    AVG

    V

    V

    2

    =

    A full-wave rectier allows current to ow duringboth the positive and negative half ccles or thefull !"0#whereas half-wave rectier allows onlduring one-half of the ccle.

    $he no. of %ve alternations is twice the half

    wave for the sa&e ti&e interval. $he output fre'uenc is twice the input

    fre'uenc.

    $he average value ( the value &easured on a

    )* volt&eter.

    63.7% of Vp

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    ~~ t the time of $ositive half!cycle of secondary indin& volta&e,t the time of $ositive half!cycle of secondary indin& volta&e,

    the u$$er end of secondary indin& becomes $ositive.the u$$er end of secondary indin& becomes $ositive.

    ~~ Under this condition, u$$er diode is in forard biased hereasUnder this condition, u$$er diode is in forard biased hereas

    loer diode is in reverse biased.loer diode is in reverse biased.

    ~~ 6ence u$$er diode conduct $ositive half!cycle of the in$ut of6ence u$$er diode conduct $ositive half!cycle of the in$ut of

    the a.c volta&e here as loer diode does not conducts.the a.c volta&e here as loer diode does not conducts.

    ~~ t the time of ne&ative half!cycle of secondary indin&, u$$ert the time of ne&ative half!cycle of secondary indin&, u$$er

    end of secondary indin& become ne&ative.end of secondary indin& become ne&ative.

    ~~ Under this condition, loer diode is in forard biased here asUnder this condition, loer diode is in forard biased here as

    u$$er diode is in reverse biased.u$$er diode is in reverse biased.

    ~~ 6ence the loer diode conduct current via load of the ne&ative6ence the loer diode conduct current via load of the ne&ative

    half!cycle of in$ut a.c volta&e and u$$er diode does nothalf!cycle of in$ut a.c volta&e and u$$er diode does notconducts current.conducts current.

    ~~ The current in the load is in same direction for both half!cycle ofThe current in the load is in same direction for both half!cycle of

    in$ut a.c volta&e. n this ay d.c out$ut is obtain across thein$ut a.c volta&e. n this ay d.c out$ut is obtain across the

    load.load.

    EE201 Semiconductor DeviceEE201 Semiconductor Device 2424

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    2$2$

    Coupled inputolt!"e

    $his &ethod of rectication e&plos twodiodesconnected to a secondar center-tapped transfor&er.

    $he i+p voltage is coupled through thetransfor&er to the center-tapped secondar.

    The Center-Tapped Full-ave!ectier

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    2%2%

    %ve half-ccle input voltage forward-bias ) reverse-bias )/-the current patch through the) and R1

    -ve half-ccle input voltage reverse-bias ) forward-bias )/-the current patch through )/

    and R1 $he output current on both portions of the input

    ccle ( sa&e direction through the load.

    $he o+p voltage across the load resistors ( full-

    wave rectiers

    The Center-Tapped Full-ave!ectier

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    - ()ect of the Turns Ratio on the Output !oltae -- ()ect of the Turns Ratio on the Output !oltae -

    priVV 2

    sec =

    7.0)()( = pripoutp VV

    2!2!

    &' n(1, )p*out+()p*pri+- 0.7V 2

    )p*sec+()p*pri+

    &' n(2,

    priVV 2sec =

    2n an case, the o+p voltage is alwasone-half of the total secondar voltage&inus the diode drop barrier potential,no &atter what the turns ratio.

    V

    V

    Vout 7.02sec

    =

    The Center-Tapped Full-ave!ectier

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    -"ea# $nverse %oltage &"$%'-

    3a4i&u& anode3a4i&u& anode

    voltage5voltage5 2

    (sec)

    1

    pVD +=

    2

    (sec)

    2

    pVD =

    )5 forward-bias ( its cathode is at the sa&e voltageof its anode &inus diode drop6 $his is also the

    voltage on the cathode of )/.PIV across D2:

    VV

    VV

    VPIV

    p

    pp

    7.0

    27.0

    2

    (sec)

    (sec)(sec)

    =

    =

    VVV

    VV

    V

    outpp

    p

    outp

    4.12

    7.02

    )((sec)

    (sec)

    )(

    +=

    =

    #e#e$now$now

    t!tt!t TuTu

    &'&' VVPIV outp 7.02 )( +=

    The Center-Tapped Full-ave!ectier

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    Brid&e *ectifierBrid&e *ectifier

    EE201 Semiconductor DeviceEE201 Semiconductor Device 2929

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    Brid&e *ectifier 3$erationBrid&e *ectifier 3$eration~~ t the time of $ositive half!cycle of secondary indin& volta&e thet the time of $ositive half!cycle of secondary indin& volta&e the

    u$$er end of the secondary indin& becomes $ositive.u$$er end of the secondary indin& becomes $ositive.~~ Under this condition diode D4 and DC are in forard biased here asUnder this condition diode D4 and DC are in forard biased here as

    other diode are in reverse biased.other diode are in reverse biased.

    ~~ 6ence the diode D4 and DC conduct current throu&h the load resistor.6ence the diode D4 and DC conduct current throu&h the load resistor.

    t the time of ne&ative half !cycle of the secondary indin& volta&e,t the time of ne&ative half !cycle of the secondary indin& volta&e,

    the loer end of the secondary indin& is $ositive.the loer end of the secondary indin& is $ositive.

    ~~ Under this condition, D2 and [email protected] are in forard biased and here asUnder this condition, D2 and [email protected] are in forard biased and here as

    other diode are in reverse biased.other diode are in reverse biased.

    ~~ 6ence the diode D2 and [email protected] conduct current throu&h the load resistor.6ence the diode D2 and [email protected] conduct current throu&h the load resistor.

    ~~ This flos of current is in same direction as for $ositive half !cycle ofThis flos of current is in same direction as for $ositive half !cycle of

    the secondary indin& volta&e.the secondary indin& volta&e.

    ~~ 6ence d.c out$ut is obtain across load resistor.6ence d.c out$ut is obtain across load resistor.

    EE201 Semiconductor DeviceEE201 Semiconductor Device 3131

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    *ectifiers in 5 meter*ectifiers in 5 meter To measure 5 current, the 5 current must first be convertedTo measure 5 current, the 5 current must first be converted

    to D5 current.to D5 current.

    This is accom$lished ith diodes calledThis is accom$lished ith diodes called rectifiers.rectifiers.

    The $rocess of convertin& 5 to D5 is calledThe $rocess of convertin& 5 to D5 is called rectification.rectification.

    The rectifiers are $laced beteen the meter in$ut and theThe rectifiers are $laced beteen the meter in$ut and themeter movement and allo current to flo in only one direction.meter movement and allo current to flo in only one direction.

    (refer fi&ure [email protected]@)(refer fi&ure [email protected]@)

    The rectifiers convert the sine ave into a $ulsatin& D5 currentThe rectifiers convert the sine ave into a $ulsatin& D5 current

    that is a$$lied to the meter movement.that is a$$lied to the meter movement.

    EE201 Semiconductor DeviceEE201 Semiconductor Device 3232

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    *ectifiers in 5 meter*ectifiers in 5 meter

    EE201 Semiconductor DeviceEE201 Semiconductor Device 3333

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    5li$$er circuits5li$$er circuits

    circuit hich removes the $ea+ of a aveform is +non as a circuit hich removes the $ea+ of a aveform is +non as aclipperclipper..

    5li$$er circuits have the ability to cli$E off a $ortion of the in$ut5li$$er circuits have the ability to cli$E off a $ortion of the in$ut

    si&nal ithout distortin& the remainin& $art of the alternatin&si&nal ithout distortin& the remainin& $art of the alternatin&

    aveform.aveform.

    There are to ty$es of cli$$er circuit, namely series andThere are to ty$es of cli$$er circuit, namely series and

    $arallel.$arallel.

    The series confi&uration is defined as the one here the diodeThe series confi&uration is defined as the one here the diode

    is in series ith the load hile the $arallel confi&uration has theis in series ith the load hile the $arallel confi&uration has the

    diode in a branch $arallel to the load.diode in a branch $arallel to the load.

    EE201 Semiconductor DeviceEE201 Semiconductor Device 3434

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    The res$onse of the series confi&uration of 'i&ure 2.44(a) due to theThe res$onse of the series confi&uration of 'i&ure 2.44(a) due to thealternatin& aveforms is $rovided in 'i&ure 2.44(b). lthou&h it as firstalternatin& aveforms is $rovided in 'i&ure 2.44(b). lthou&h it as first

    introduced as a half!ave rectifier (for sinusoidal aveforms), there areintroduced as a half!ave rectifier (for sinusoidal aveforms), there are

    no boundaries on the ty$e of si&nals that can be a$$lied to a cli$$er.no boundaries on the ty$e of si&nals that can be a$$lied to a cli$$er.

    EE201 Semiconductor DeviceEE201 Semiconductor Device 3535

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    5li$$er circuits5li$$er circuits

    The netor+ of 'i&ure 2.42 is the sim$lest $arallel diode confi&urationsThe netor+ of 'i&ure 2.42 is the sim$lest $arallel diode confi&urationsith the out$ut aveform obtained due to the suare aveform in$ut.ith the out$ut aveform obtained due to the suare aveform in$ut.

    The analysis of $arallel confi&uration is very similar to that a$$lied toThe analysis of $arallel confi&uration is very similar to that a$$lied to

    series confi&urations.series confi&urations.

    EE201 Semiconductor DeviceEE201 Semiconductor Device 3636

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    The clam$in& netor+ clam$E a si&nal to different dc level. TheThe clam$in& netor+ clam$E a si&nal to different dc level. The

    netor+ ill have a ca$acitor, a diode and a resistive element.netor+ ill have a ca$acitor, a diode and a resistive element. The ma&nitude ofThe ma&nitude of and must e chosen such and must e chosen such that the timethat the time

    constantconstant t ( is large enough to ensure that the voltaget ( is large enough to ensure that the voltage

    across the capacitoracross the capacitor does not dischar&e si&nificantly durin& thedoes not dischar&e si&nificantly durin& the

    interval the diode is non!conductin&.interval the diode is non!conductin&.

    Throu&hout the analysis e ill assume that for all $racticalThrou&hout the analysis e ill assume that for all $ractical

    $ur$oses the ca$acitor ill be fully char&ed.$ur$oses the ca$acitor ill be fully char&ed.

    EE201 Semiconductor DeviceEE201 Semiconductor Device 3737

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    EE201 Semiconductor DeviceEE201 Semiconductor Device 3838

    Durin# t%e interv$ 0 *+2 t%e net,or- ,i $&&e$r $s s%o,n in i#ure

    2.14($) ,it% t%e diode in t%e /on st$te effective /s%ortin# out t%eeffect of t%e resistor .

    Durin# t%is interv$ t%e out&ut vot$#e is direct $cross t%e s%ort

    circuit $nd v0 0 ". %en t%e in&ut s,itc%es to t%e " st$te! t%e net,or- ,i $&&e$r $s

    s%o,n in i#ure 2.14() ,it% t%e o&en circuit euiv$ent for t%e diode

    determined t%e $&&ied si#n$. Since v0 is in &$r$e ,it% t%e diode $nd resistor. &&in# irc%%offs vot$#e $, $round t%e in&ut oo& ,i resut in

    *%e ne#$tive si#n resutin# from t%e f$ct t%$t t%e &o$rit of 2" is

    o&&osite to t%e &o$rit defined for v0. *%e out&ut si#n$ is c$m&ed to 0 " for t%e interv$ 0 to *+2 ut

    m$int$ins t%e s$me tot$ s,in# (2") $s t%e in&ut. i#ure 2.15 s%o,s t%e

    out&ut ,$veform for t%e c$m&er.

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    EE201 Semiconductor DeviceEE201 Semiconductor Device 3939

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    00

    * Clamper *pplication(

    A cla&ping circuit is often used in $V

    receivers as a dc restorer.$he inco&ing co&posite video signal is

    nor&all processed through capacitivelcoupled a&pliers that eli&inate the dcco&ponent, thus losing blac8 and whitereference levels and the blan8ing level.Before applied to the picture tube, thesereference level &ust be restored.

    +iode Clampers

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    11

    $he data sheet for diodes and other devicesgives detailed information about speciccharacteristics such as the various

    maximum current and voltage ratings,temperature range, and voltage versuscurrent curves V-2 characteristic.

    2t is so&eti&es a ver valuable piece of

    infor&ation, even for a technician. $here arecases when ou &ight have to select areplace&ent diode when the tpe of diodeneeded &a no longer be available.

    $hese are the absolute &a4. values under

    The +iode +ata heet

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    22

    3ating3ating +y!bo+y!bo

    ll1450014500

    111450014500

    //14501450

    060674T74T

    ea, repetitive reverseea, repetitive reversevoltagevoltage

    or,ing pea, reverseor,ing pea, reverse

    voltagevoltage

    DC bloc,ing voltageDC bloc,ing voltage

    VVRR3RR3

    VVR73R73

    VVRR

    9090 100100 /00/00 &&

    4onrepetitive pea,4onrepetitive pea,reverse voltagereverse voltage

    VVR;3R;3 :0:0 1/01/0 /50/50 &&

    r!s reverse voltager!s reverse voltage VVRr&sRr&s 6969 *0*0 150150 &&

    Average rectiedAverage rectied

    forward current (single%forward current (single%phase resistive loadphase resistive load

    :0; T:0; TAA< *9< *9ooCC

    22oo

    11

    AA

    4onrepetitive pea,4onrepetitive pea,surge current (surgesurge current (surge

    applied at rated loadapplied at rated load

    22F;3F;360 (for60 (for

    11

    AA

    Maximum !ating

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    33$I%&'E "()*$I%&'E "()*

    selection of rectifier diodes based on ma#imum ratin&s of selection of rectifier diodes based on ma#imum ratin&s of

    33, , '0F'0F, and , and **F**F..

    Maximum !ating

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    -//* D3D/-//* D3D/

    ~ used to $roduce a stabili

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    !" characteristics!" characteristics

    EE201 Semiconductor DeviceEE201 Semiconductor Device 4545

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    dvanta&es of Diode

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    [email protected]!ple 1#[email protected]!ple 1#

    145*50 10& ener diode145*50 10& ener diode

    !int!in

    o)p olt!"e

    i)p !*+ f*o,-.//V 0 31V

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    -ight Emitting Dioe -ED-ight Emitting Dioe -ED~~ are often used as small indicator li&hts on electronic devicesare often used as small indicator li&hts on electronic devices

    and increasin&ly in hi&her $oer a$$lications such as flashli&htsand increasin&ly in hi&her $oer a$$lications such as flashli&htsand area li&htin&.and area li&htin&.

    ~ 0chematic Dia&ram~ 0chematic Dia&ram

    EE201 Semiconductor DeviceEE201 Semiconductor Device 4848

    5atho

    de node

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    /D 5haracteristics/D 5haracteristics~~ Ahen a /D is forard biased (sitched on), electrons areAhen a /D is forard biased (sitched on), electrons are

    able to recombine ith electron hole ithin the device,able to recombine ith electron hole ithin the device,

    releasin& ener&y in the form of $hotons.releasin& ener&y in the form of $hotons.

    ~~ This effect is called electroluminescene and the color of theThis effect is called electroluminescene and the color of the

    li&ht is determined by the ener&y &a$ of the semiconductor.li&ht is determined by the ener&y &a$ of the semiconductor.~~ /Ds $resent many advanta&es over incandescent li&ht/Ds $resent many advanta&es over incandescent li&ht

    sources includin& loer ener&y consum$tion, lon&er lifetime,sources includin& loer ener&y consum$tion, lon&er lifetime,

    im$roved robustness, smaller si

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    /D $$lication/D $$lication

    EE201 Semiconductor DeviceEE201 Semiconductor Device 5050

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    hotodiodehotodiode

    EE201 Semiconductor DeviceEE201 Semiconductor Device 5151

    http://www.google.com.my/imgres?imgurl=http://4.bp.blogspot.com/_RA2btAL9GeE/SL1ReSw_DjI/AAAAAAAAAPA/hmpVOR-h0eA/s400/Photodiode.jpg&imgrefurl=http://ssecganesh.blogspot.com/2008/09/introduction-to-photodiodes.html&usg=__L98yHT8dn-ryG8M8GMI5NqIPubQ=&h=359&w=359&sz=8&hl=en&start=1&zoom=1&tbnid=8g5Di02jhfl43M:&tbnh=121&tbnw=121&prev=/images%3Fq%3Dphotodiode%26hl%3Den%26gbv%3D1%26tbs%3Disch:1&itbs=1http://www.google.com.my/imgres?imgurl=http://www.epn-online.com/lib/image.php%3Furi%3D/content/USER/jhappich/.bin.WEB.1190625884184.jpg&imgrefurl=http://www.epn-online.com/page/new51544/photodiode-detector-for-photon-counting-applications.html&usg=__Rlzuu1uVfay5a7SzRFMYgaaaNic=&h=300&w=365&sz=29&hl=en&start=20&zoom=1&tbnid=w3z71NZW29I0LM:&tbnh=99&tbnw=121&prev=/images%3Fq%3Dphotodiode%26hl%3Den%26gbv%3D1%26tbs%3Disch:1&itbs=1http://www.google.com.my/imgres?imgurl=http://rocky.digikey.com/weblib/Optek/Web%2520photos/OP950.jpg&imgrefurl=http://parts.digikey.com/uk/4/indexd329.html&usg=__EUXjgCNPvAiC8GWM9_eXVjVEYQY=&h=640&w=640&sz=233&hl=en&start=19&zoom=1&tbnid=JsxnBV08Znd7gM:&tbnh=137&tbnw=137&prev=/images%3Fq%3Dphotodiode%26hl%3Den%26gbv%3D1%26tbs%3Disch:1&itbs=1
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    hotodiode 5haracteristicshotodiode 5haracteristics

    0hotoioe0hotoioeis a ty$e of $hotodetector ca$able of convertin&is a ty$e of $hotodetector ca$able of convertin&

    li&ht into either current or volta&e, de$endin& u$on the mode ofli&ht into either current or volta&e, de$endin& u$on the mode of

    o$eration.o$eration.

    ~~ hotodiodes are similar to re&ular semiconductor diodeshotodiodes are similar to re&ular semiconductor diodese#ce$t that they may be either e#$osed (to detect vacuum U"e#ce$t that they may be either e#$osed (to detect vacuum U"

    or H!rays) or $ac+a&ed ith a indo or o$tical fiberor H!rays) or $ac+a&ed ith a indo or o$tical fiber

    connection to allo li&ht to reach the sensitive $art of theconnection to allo li&ht to reach the sensitive $art of the

    device.device.

    ~~ Fany diodes desi&ned for use s$ecifically as a $hotodiode illFany diodes desi&ned for use s$ecifically as a $hotodiode illalso use a ;unction rather than the ty$ical ;unction.also use a ;unction rather than the ty$ical ;unction.

    EE201 Semiconductor DeviceEE201 Semiconductor Device 5252

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    hotodiode $$licationhotodiode $$lication

    ! $hotodiodes are used in similar a$$lications to other! $hotodiodes are used in similar a$$lications to other

    $hotodetectors, such as $hotoconductors, char&e!cou$led$hotodetectors, such as $hotoconductors, char&e!cou$led

    devices , and $hotomulti$lier tubes.devices , and $hotomulti$lier tubes.

    hotodiodes are used in consumer electronics devices such ashotodiodes are used in consumer electronics devices such ascom$act disc $layers, smo+e detectors, and the receivers forcom$act disc $layers, smo+e detectors, and the receivers for

    remote controls in "5*s and televisions.remote controls in "5*s and televisions.

    EE201 Semiconductor DeviceEE201 Semiconductor Device 5353

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    aser Diode 5haracteristicsaser Diode 5haracteristics mall si+e an 2eight mall si+e an 2eight: ty$ical laser diode measures less: ty$ical laser diode measures less

    than one millimeter across and ei&hs a fraction of a &ram,than one millimeter across and ei&hs a fraction of a &ram,

    ma+in& it ideal for use in $ortable electronic eui$ment.ma+in& it ideal for use in $ortable electronic eui$ment.

    -o2 current, voltage, an po2er re3uirements: -o2 current, voltage, an po2er re3uirements:Fost laserFost laser

    diodes reuire only a fe mill atts of $oer at @ to 42 voltsdiodes reuire only a fe mill atts of $oer at @ to 42 volts

    D5 and several mill am$eres. Therefore, they can o$erateD5 and several mill am$eres. Therefore, they can o$erate

    usin& small battery $oer su$$lies.usin& small battery $oer su$$lies.

    -o2 intensit4: -o2 intensit4: laser diode cannot be used for s$ectacular laser diode cannot be used for s$ectacular

    $ur$oses such as burnin& holes in metal, brin&in& don$ur$oses such as burnin& holes in metal, brin&in& don

    satellites, or blindin& aircraft $ilots. evertheless, its coherentsatellites, or blindin& aircraft $ilots. evertheless, its coherent

    out$ut results in hi&h efficiency and ease of modulation forout$ut results in hi&h efficiency and ease of modulation for

    communications and control a$$lications.communications and control a$$lications.

    5ie(angle 6eam: 5ie(angle 6eam: laser diode $roduces a GconeG rather laser diode $roduces a GconeG rather

    than a G$encilG of visible li&ht or *, althou&h this GconeG can bethan a G$encilG of visible li&ht or *, althou&h this GconeG can be

    collimated usin& conve# lenses.collimated usin& conve# lenses.

    EE201 Semiconductor DeviceEE201 Semiconductor Device 5555

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    aser Diode $$licationaser Diode $$lication~~ aser diodes find ide use in telecommunication as easilyaser diodes find ide use in telecommunication as easily

    modulated and easily cou$led li&ht sources for fiber o$ticsmodulated and easily cou$led li&ht sources for fiber o$ticscommunication.communication.

    ~ They are used in various measurin& instruments, such as~ They are used in various measurin& instruments, such as

    ran&efinders. nother common use is in barcode readers.ran&efinders. nother common use is in barcode readers.

    ~ "isible lasers, ty$ically red but later also &reen, are common~ "isible lasers, ty$ically red but later also &reen, are common

    as laser $ointers.as laser $ointers.

    ~ Both lo and hi&h!$oer diodes are used e#tensively in the~ Both lo and hi&h!$oer diodes are used e#tensively in the

    $rintin& industry both as li&ht sources for scannin& (in$ut) of$rintin& industry both as li&ht sources for scannin& (in$ut) of

    ima&es and for very hi&h!s$eed and hi&h!resolution $rintin&ima&es and for very hi&h!s$eed and hi&h!resolution $rintin&

    $late (out$ut) manufacturin&.$late (out$ut) manufacturin&.

    ~ nfrared and red laser diodes are common in 5D $layers, 5D!~ nfrared and red laser diodes are common in 5D $layers, 5D!

    *3Fs and D"D technolo&y. "iolet lasers are used in 6D D"D*3Fs and D"D technolo&y. "iolet lasers are used in 6D D"D

    and Blu!ray technolo&y.and Blu!ray technolo&y.

    EE201 Semiconductor DeviceEE201 Semiconductor Device 5656

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    IU5% */"031.IU5% */"031.

    EE201 Semiconductor DeviceEE201 Semiconductor Device 5757

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    5onclusion5onclusion~~ Understand the characteristics of diode and diode as a semiconductorUnderstand the characteristics of diode and diode as a semiconductor

    device.device.

    ~~ Determine !" characteristic curve for silicon diode and e#$lain:Determine !" characteristic curve for silicon diode and e#$lain:

    a. %nee "olta&e (Threshold volta&e )a. %nee "olta&e (Threshold volta&e )

    b. 'orard current (in milli m$ere scale)b. 'orard current (in milli m$ere scale)

    c. *everse current (in microm$ere scale)c. *everse current (in microm$ere scale)

    d. Brea+don volta&ed. Brea+don volta&e

    e. Burnin& level (hen d, "d e#ceeds ma#)e. Burnin& level (hen d, "d e#ceeds ma#)

    ~~ %no diode a$$lications as rectifiers.%no diode a$$lications as rectifiers.

    ~~ Diode as cli$$er and clam$er circuits.Diode as cli$$er and clam$er circuits.

    ~~

    Understand other ty$es of diode:Understand other ty$es of diode:

    a. -ener diodea. -ener diode

    b. i&ht emittin& diode (/D)b. i&ht emittin& diode (/D)

    c. hotodiodec. hotodiode

    d. aser dioded. aser diode

    EE201 Semiconductor DeviceEE201 Semiconductor Device 5858

    ?*3U D05U003?*3U D05U003

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    ?*3U D05U003?*3U D05U003

    6alf ave rectifier!fahmi,afi,a+mal6alf ave rectifier!fahmi,afi,a+mal

    'ull ave rectifier!lo+man,hafi