Types of Transistor

7/25/2019 Types of Transistor

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Technological University of the Philippines

College of Engineering

Electronics Engineering Department

ELE 8L INDUSTRIAL ELECTRONICS, LAB

Assignment No !

TYPES OF TRANSISTORS

Timpoc, arielle !"


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BS ECE "B

Engr" a" #ictoria $" Pa%illaInstr#ctor

$an#ar% &8, '&!(

'n)Semester S* '&!(+'&!

&" !IPO'AR (UN$TION TRANSISTORS )!(T*

Bipolar $#nction Transistor -B$T. is consists of t/ree+la%er 0san)1ic/2 of )ope)

-e3trinsic. semicon)#ctor materials 1/ic/ comes in t1o )ifferent polarit% 4iasing5 N6N an)

6N6 As t/e name itself, it is consists of t1o 6+N 7#nction similar to )io)e t/#s, it can 4e eit/er

for1ar) 4iase) or reerse) 4iase) T/e N6N )eice /as one p region 4et1een t1o n regions

an) t/e 6N6 )eice /as one n region 4et1een t1o p regions

B$T /as t/ree terminals 9no1n as Emitter -E., Base -B. an) Collector -C. Eac/ region

)iffers in 4ot/ geometricall% an) in terms of )oping concentration t/erefore, Emitter an)

Collector are not electricall% s%mmetric an) terminals cannot 4e interc/ange)


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Operation of a !ipolar (+nction Transistor


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Consi)ering a N6N transistor, t/e Base+Emitter -B+E. 7#nction is for1ar) 4iase) an)

Base+Collector -C+E. 7#nction is reerse) 4iase) T/e electrons moe from t/e 4ase to emitter

an) t/e /oles moes to1ar) t/e 4ase t/#s, recom4ination occ#r t/at allo1s a c#rrent to flo1

across t/e B+E 7#nction :o1eer, t/e )oping leel in t/e 4ase is er% lo1 an) t/in T/is means

t/e most of t/e electrons are a4le to trael across t/is region 1it/o#t recom4ining 1it/ t/e /oles

As a res#lt t/e electrons migrate to1ar)s t/e collector, 4eca#se t/e% are attracte) 4% t/e positie

potential In t/is 1a% t/e% are a4le to flo1 across 1/at is effectiel% a reerse 4iase) 7#nction,

an) c#rrent flo1s in t/e collector circ#it

T/e collector c#rrent is significantl% /ig/er t/an t/e 4ase c#rrent, an) 4eca#se t/e

proportion of electrons com4ining 1it/ /oles remains t/e same t/e collector c#rrent is al1a%s

proportional to t/e 4ase c#rrent In ot/er 1or)s ar%ing t/e 4ase c#rrent aries t/e collector

c#rrent

Same principle is applie) in 6N6 transistor e3cept t/at t/e ma7orit% carrier is /oles

instea) of electrons an) oltages are reerse)

$haracteristic $+rve of a !ipolar (+nction Transistor


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C/aracteristic C#re of B$T

ApplicationUses !ipolar (+nction Transistor

S-itch

Transistors ma% 4e #se) as s1itc/ing elements to control DC po1er to a loa) T/e

s1itc/e) -controlle). c#rrent goes 4et1een emitter an) collector; t/e controlling c#rrent goes

4et1een emitter an) 4ase


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Transistor transistor logic -TTL. is a )igital logic )esign in 1/ic/ 4ipolar transistors act

on )irect c#rrent p#lses It implements logical f#nction s#c/ as NOT, AND, OR, NAND, NOR

an) ot/ers

Amplifier


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/" FIE'0 EFFE$T TRANSISTORS )FET*

>iel) Effect Transistor is a #nipolar transistor T/e c#rrent is transporte) 4% carriers of

one polarit% -ma7orit%., 1/ereas in t/e conentional 4ipolar transistor carriers of 4ot/

polarities -ma7orit% an) minorit%. are inole) T/e famil% tree of >ET )eices ma% 4e )ii)e)

into t1o main 4ranc/es, $#nction >ETs -$>ETs. an) ?etal+O3i)e Semicon)#ctor >ETs

-?OS>ETs. $#nction >ETs are in/erentl% )epletion+mo)e )eices, an) are aaila4le in 4ot/

n+ an) p+c/annel config#rations ?OS>ETs are aaila4le in 4ot/ en/ancement an) )epletion

mo)es, an) also e3ist as 4ot/ n+ an) p+c/annel )eices T/e t1o main >ET gro#ps )epen) on

)ifferent p/enomena for t/eir operation >ET is consist also of t/ree terminals5 @ate -@., Drain

-D. an) So#rce -S.

Operation of Fiel% Effect Transistor


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(+nction Fiel% Effect Transistor )(FET*

T/e c#rrent in t/e c/annele) is controlle) 4% t/e gate oltage T/e control of t/e

c#rrent in one part of t/e )eice 4% t/e oltage in anot/er part of t/e )eice is t/e 4asic

transistor action T/e p+n $>ET is a 0normall% on2, or )epletion mo)e, )eice; t/at is, a oltage

m#st 4e applie) to t/e gate terminal to t#rn t/e )eice off Consi)er t/e sit#ation in 1/ic/ t/e

gate oltage is =ero, t/e )rain oltage c/anges As t/e )rain oltage increases to more positie,

t/e gate+to+c/annel p+n 7#nction 4ecomes reerse 4iase) near t/e )rain terminal, an) t/e space+

c/arge region 1i)ens, e3ten)ing fart/er into t/e c/annel T/e c/annel acts essentiall% as a

resistor, an) t/e effectie c/annel resistance increases as t/e space+c/arge region 1i)ens;

t/erefore t/e slope of t/e IDan) DSc/aracteristics )ecreases T/e effectie c/annel resistance

no1 aries along t/e c/annel lengt/, an) since t/e c/annel c#rrent m#st 4e constant, t/e

oltage )rop t/ro#g/ t/e c/annel 4ecomes in)epen)ent on position

If t/e )rain oltage increases f#rt/er, t/e c/annel #n)ergo pinc/ off con)ition 1/ic/

isolates t/e so#rce an) )rain terminals t/#s, )rain c#rrent is =ero an) t/e )rain oltage is

sat#rate)


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etal1O2i%e Semicon%+ctor Fiel% Effect Transistor )OSFET*

ET T/e so#rce terminal s#pplies carrier t/at flo1s t/ro#g/ t/e c/annel an) t/e

)rain terminal allo1s t/e carrier to )rain from t/e c/annel >or N?OS transistor, t/e electrons

flo1 from t/e so#rce to t/e )rain 1it/ an applie) )rain+to+so#rce oltage, 1/ic/ means t/at

t/e conentional c#rrent enters t/e )rain an) leaes t/e so#rce T/e magnit#)e of t/e c#rrent is

a f#nction of t/e amo#nt of c/arge in t/e inersion la%er, 1/ic/ is in t#rn a f#nction of t/e

oltage in t/e gate terminal Since t/e gate is ins#late) 4% an o3i)e, t/ere is no gate c#rrent as

1ell as t/e s#4strate Same principle is applie) to 6?OS 4#t reerse) in polarit%

$haracteristic $+rve of FET


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(+nction Fiel% Effect Transistor )(FET* $haracteristic $+rve

etal1O2i%e Semicon%+ctor Fiel% Effect Transistor )OSFET* $haracteristic $+rve

ApplicationUses !ipolar (+nction Transistor

S-itch


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T/e p+n $>ET is a 0normall% on2 )eice; t/at is, a oltage m#st 4e applie) to t/e gate

terminal to t#rn t/e )eice off >or ?OS>ET, t/e )eice is on at sat#ration region an) off at

c#t+off region

$hopper

A )irect+co#ple) amplifier can 4e 4#ilt 4% leaing o#t t/e co#pling an) 4%pass

capacitors an) connecting t/e o#tp#t of eac/ stage )irectl% to t/e inp#t of ne3t stage T/#s

)irect c#rrent is co#ple), as 1ell as alternating c#rrent T/e ma7or )ra14ac9 of t/is met/o) is

occ#rrence of )rift, a slo1 s/ift in t/e final o#tp#t oltage pro)#ce) 4% s#ppl% transistor, an)

temperat#re ariations

+ltiple2er


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An analog m#ltiple3er, a circ#it t/at steers one of t/e inp#t signals to t/e o#tp#t line, is

s/o1n in fig#re In t/is circ#it eac/ $>ET acts as a single+pole single+t/ro1 s1itc/


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$>ET can incorporate t/e amplif%ing action as 1ell as fee)4ac9 action It, t/erefore,

acts 1ell as a p/ase s/ift oscillator T/e /ig/ inp#t impe)ance of >ET is especiall% er%

al#a4le in p/ase+s/ift oscillators in or)er to minimi=e t/e loa)ing effect

$+rrent 'imiter

$>ET c#rrent limiting circ#it is s/o1n in fig#re Almost all t/e s#ppl% oltage

t/erefore appears across t/e loa) ET

into actie region, 1/ere it limits t/e c#rrent to 8 mA T/e $>ET no1 acts as a c#rrent so#rce

an) preents e3cessie loa) c#rrent

3" UNI(UN$TION TRANSISTOR )U(T*


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U$T is also calle) t/e )o#4le+4ase )io)e is a '+la%er, +terminal soli)+state s1itc/ing

)eice It is consists of a lig/tl% )ope) N+t%pe silicon 4ar 1it/ a small piece of /eail% )ope)

6+t%pe material allo%e) to its one si)e to pro)#ce single p+n 7#nction T/e t/ree terminals are

Base+! -B!., Base+' -B'. an) Emitter -E. T/e emitter region is #s#all% locate) closer to 4ase+'

t/an Base+! for as%mmetr%

Operation of Uni4+nction Transistor


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+ltivi5rator

T/is stan)ar) circ#it can 4e t#rne) #p+si)e+)o1n if nee)e) T/e animation 4elo1

s/o1s /o1 one si)e of t/e m#ltii4rator t#rns on t/en t/e ot/er si)e to actiate eac/ LED In

t/e circ#it a4oe, t/e m#ltii4rator ta9es t/e "9 to t/e positie rail, to actiate t/e tone

circ#it


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6" SI'I$ON1$ONTRO''E0 RE$TIFIER )S$R* or T7YRISTOR

T/e SCR is a fo#r+la%er, t/ree+7#nction an) a t/ree+terminal )eice T/e en) 6+region is

t/e ano)e, t/e en) N+region is t/e cat/o)e an) t/e inner 6+region is t/e gate T/e ano)e to

cat/o)e is connecte) in series 1it/ t/e loa) circ#it Essentiall% t/e )eice is a s1itc/

T/ese t1o )eices can 4e recogni=e) as t1o transistors T/e #pper left one is 6+N+6

transistor an) t/e lo1er rig/t N+6+N t%pe >#rt/er it can 4e recogni=e) t/at t/e 4ase of t/e 6+

N+6 transistor is 7oine) to t/e collector of t/e N+6+N transistor 1/ile t/e collector of 6+N+6 is

7oine) to t/e 4ase of N+6+N transistor, as ill#strate) in fig c T/e gate terminal is 4ro#g/t o#t

from t/e 4ase of t/e N+6+N material T/is constr#ction /as 4een conceie) merel% to e3plain

t/e 1or9ing of SCR, ot/er1ise in p/%sical s/ape t/e SCR /as fo#r soli) la%ers of 6+N+6+N

t%pe onl%

Operation of Silicon1$ontrolle% Rectifier


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ApplicationUses of Silicon1$ontrolle% Rectifier

Po-er $ontrol


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In ac circ#its t/e SCR can 4e t#rne)+on 4% t/e gate at an% angle H 1it/ respect to applie)

oltage T/is angle H is calle) t/e firing angle an) po1er control is o4taine) 4% ar%ing t/e

firing angle T/is is 9no1n as p/ase control T/e SCR 1ill t#rn+off 4% nat#ral comm#tation

1/en t/e c#rrent 4ecomes =ero

6o1er control in )c circ#its is o4taine) 4% ar%ing t/e )#ration of on+time an) off+time of

t/e )eice an) s#c/ a mo)e of operation is calle) on+off control or c/opper control

S-itch

T/%ristor, 4eing 4ista4le )eice is 1i)el% #se) for s1itc/ing of po1er signals o1ing to

t/eir long life, /ig/ operation spee) an) free)om from ot/er )efects associate) 1it/

mec/anical an) electro+mec/anical s1itc/es


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P+lse $irc+it

SCRs are #se) for pro)#cing /ig/ oltagec#rrent p#lses of )esire) 1aeform an)

)#ration T/e capacitor C is c/arge) )#ring t/e positie /alf c%cle of t/e inp#t s#ppl% an) t/e

SCR is triggere) )#ring t/e negatie /alf+c%cle T/e capacitor 1ill )isc/arge t/ro#g/ t/e

o#tp#t circ#it, an) 1/en t/e SCR for1ar) c#rrent 4ecomes =ero, it 1ill t#rn+off

Over1#oltage Protection

SCRs can 4e emplo%e) for protecting ot/er e#ipment from oer+oltages o1ing to t/eir

fast s1itc/ing action T/e SCR emplo%e) for protection is connecte) in parallel 1it/ t/e loa)


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Types of Transistor