diod rectifier

7/23/2019 Diod Rectifier

1/35

DEE 2023 SEMICONDUCTOR DEVICES

CHAPTER 2

DIODES


2/35

DEE2023 SEMICONDUCTOR DEVICES 2

2.1 CHARACTERISTICS OF DIODE & DIODE AS A

SEMICONDUCTOR DEVICES

2.1.1 The schematics diagram and physical structure of a diode

2.1 Schematic diagram, physical and and schematic symbol of a diode

a. Schematic diagram of a diode is same as PN com!i"atio".!. # diode ha$e 2 %i"s e&ectro"ic com%o"e"t 'hich is ca&&ed a"ode a"d

cathode.c. Anodeis a P t(%e materia& a"d Cathodeis a N t(%e materia&.

d. The arro' from the diagram sho's the c)rre"t co"$e"tio"a& directio".


3/35




2.1.2 The schematics diagram of a diode in BIAS V!TA"#

2.1 $or%ard bias &a' and (e)erse bias &b' circuit diagrams

The $o&tage across the diode ca&& !iased $o&tage.a. $or%ard bias

If a"ode get $o&tage more positi)e from cathode* or cathode get$o&tage more "egati$e from a"ode.

b. (e)erse biasIf a"ode get $o&tage more negati)e than cathode or cathode get

more %ositi$e tha" a"ode.

&a' &b'


4/35

DEE2023 SEMICONDUCTOR DEVICES +



2.1.* The I+V Characteristics Cur)e for iode,he" a diode i" for'ard a"d re$erse !ias co"ditio" a"d each ofthe !ias a"d c)rre"t $a&)e are meas)red* the" IV C)r$e 'i&&a%%ear &i-e i" diagram.


5/35

DEE2023 SEMICONDUCTOR DEVICES

a. Forward current (Id

The c)rre"t %assed thro)gh the diode 'he" the diode i" for'ard!ias co"ditio". Id meas)red i" !A.

". Re#er$e current (I$' The sma&& c)rre"t %assed thro)gh the diode 'he" the diode is i"

re$erse !ias co"ditio". Is meas)red i" A&starti"g 0./#'.

c. %nee #ota'e imit $o&tage 'he" for'ard c)rre"t is s)dde"&( i"creased. 1"ee

$o&tage is simi&ar 'ith !arrier $o&tage. Si 0.4 V* 5e 0.3 V6

d. rea)down Vota'e

imit $o&tage 'here re$erse c)rre"t s)dde"&( ha%%e". 7)gec)rre"t that e8ceed the &imit ca" ca)se the ma&f)"ctio" of PN9)"ctio".

e. urn*n' e#e ,he" Id*Vd e8ceeds Pma8

2.1.* The I+V Characteristics Cur)e for iode - Cont.


6/35

DEE2023 SEMICONDUCTOR DEVICES :

2.2 DIODE IN RECTIFIERS CIRCUITS

2.2.1 Bloc iagram f /o%er Supply

AC

V!TA"#T(A0S$(#( (#CTI$I#( $I!T#( (#"!AT(

V!TA"#

#VI#(

DCVOT#5

2.2 3 Bloc diagram for C po%er supplySu!!ar+ ,-

The a.c. $o&tage* t(%ica&&( 2+0V is co""ected to tra"sformer* 'hich ste%s that ac$o&tage do'" to the &e$e& for the desired dc o)t%)t. # diode rectifier the" %ro$ides af)&&'a$e rectified $o&tage that it i"itia&&( fi&tered !( a sim%&e ca%acitor fi&ter to

%rod)ce a dc $o&tage. This res)&ti"g dc $o&tage that "ot o"&( has m)ch &ess ri%%&e$o&tage !)t a&so remai"s the same dc $a&)e e$e" if the i"%)t dc $o&tage $ariessome'hat or the &oad co""ected to the o)t%)t dc $o&tage cha"ges. This $o&tagereg)&atio" is )s)a&&( o!tai"ed )si"g o"e of a ")m!er of %o%)&ar $o&tage reg)&ator IC)"its.


7/35DEE2023 SEMICONDUCTOR DEVICES 4

2.2.1 Bloc iagram f /o%er Supply - Cont.

2.2.2 Type of rectifiers

a. 7a&f ,a$e Rectifiers

!. ;)&& ,a$e Rectifiersc.


8/35DEE2023 SEMICONDUCTOR DEVICES =


a. 4alf 5a)e (ectifiers

/#(ATI03 uring input signal positi)e cycle

Diode D for'ard !ias. D act as c&osed s'itch so c)rre"t ca" gothro)gh. Vo&tage dro% at R is e>)a& to %ositi$e c(c&e i"%)t sig"a&

%ositi$e mag"it)de

uring input signal negati)e cycle

D re$erse !ias a"d act as o%e" s'itch so c)rre"t ca""ot gothro)gh. Vo&tage dro% at R d)ri"g "egati$e c(c&e is e>)a& to ?ero


9/35

DEE2023 SEMICONDUCTOR DEVICES @

2.2 DIODE IN RECTIFIERS CIRCUITSa. $ull 5a)e (ectifiers


M termi"a& 'i&& !e %ositi$e a"d N "egati$e. Diode D/ a"d D3 'i&& !e for'ard!ias mea"'hi&e diode D2 da" D+ get re$erse !ias. C)rre"t 'i&& !e f&o' a&o"gM* E* #*


10/35/0

2.2 DIODE IN RECTIFIERS CIRCUITSa. Bridge (ectifiers


M termi"a& 'i&& !e %ositi$e a"d N "egati$e. Diode D/ a"d D3 'i&& !e for'ard!ias mea"'hi&e diode D2 da" D+ get re$erse !ias. C)rre"t 'i&& !e f&o' a&o"gM* E* #*


11/35//


2.2.* #6uations of A)erage Current, A)erage Voltage and

(oots eans S6uare Voltage


12/35

DEE2023 SEMICONDUCTOR DEVICES /2

2.2.* #6uations of A)erage Current, A)erage Voltage and

(oots eans S6uare Voltage + Cont.


13/35

# ha&f 'a$e rectifier !)i&d i" :0 Vrms i" the seco"dar( of thetra"sformer. Ca&c)&ateA

i.,hat is the o)t%)t $o&tage.ii.#$erage $o&tage of the circ)it

DEE2023 SEMICONDUCTOR DEVICES /3

#7A/!# 1


14/35DEE2023 SEMICONDUCTOR DEVICES/+

Solution 3

i. utput )oltage, Vo

1"o'" that* Vo V% sec B 0.4V

;rom form)&a* V% sec 2 8 Vrms 2 8 :0 =+.= V

Therefore* Vo V% sec B 0.4V =+.= B 0.4 =+./:V

ii. A)erage )oltage, Va)g 1"o'" that* Va$g Vo

=+./:

2:.4 V


15/35

/002 A /

/-V%%ri6

V%sec6

DEE2023 SEMICONDUCTOR DEVICES /

#7A/!# 2

Determi"eA

i. O)t%)t $o&tageii. #$erage $o&tageiii. #$erage c)rre"t


16/35

DEE2023 SEMICONDUCTOR DEVICES /:

Solution 3


1"o'" that* Vo V% sec B 0.4V 2

;rom form)&a* V% sec N sec6 V% %ri6 N %ri

/6 8 /006 2

0 V

Therefore* Vo 0 B 0.4V 2

2+.3 V

ii. A)erage )oltage, Va)g Va$g 2Vo

2 2+.36

/. V

iii. A)erage )oltage, Va)g Ia$g Va$g R

/.

1K

/.m#


17/35

2-220V

#7A/!# *

I" a ce"treta% f)&& 'a$e rectifier* &oad resista"ce is 21.The a.c. s)%%&( across the %rimar( 'i"di"g is 220V.Ta-i"g tra"sformer t)r" ratio N/N2 F a"dNeg&ecti"g diode resista"ce. Determi"eA

i. O)t%)t $o&tageii. #$erage $o&tageiii. #$erage c)rre"t

DEE2023 SEMICONDUCTOR DEVICES/4


18/35DEE2023 SEMICONDUCTOR DEVICES/=

ii. A)erage )oltage, Va)g

1"o'" that* Va$g 2Vo

22206

/+0 V

Solution 3


1"o'" that* Vo V% sec B 0.4V

2 ;rom form)&a* V% sec N sec6 V% %ri6 N %ri

26 8 2206 /

++0 VTherefore* Vo ++0 B 0V 2

220 Viii. A)erage )oltage, Va)g

Ia$g Va$g R

/+0 40m# 2K


19/35

#7A/!# 83

# f)&& 'a$e rectifier 'ith a /20 Vrms si")sodia& i"%)t had a &oad

resistor of /1. If si&ico"e diodes are em%&o(ed* determi"eA

i. #$erage $o&tage a$ai&a!&e at the &oad.ii. #$erage c)rre"t

/20Vrms

2-

DEE2023 SEMICONDUCTOR DEVICES/@


20/35EE2023 SEMICONDUCTOR DEVICES

20

Solution 3

i. A)erage )oltage, Va)g

Va$g 2Vo

1"o'" that* Vo V% sec B /.+V

;rom form)&a* V% sec 2 8 Vrms 2 8 /20

/:@.4 V

So* Vo V% sec B /.+V /:@.4 B /.+V

/:=.3 V

ii. A)erage Current

Ia$g Va$g

R /04./ /04./m# /K

#$erage $o&tage* Va$gVa$g 2Vo

2 8 /:=.3 /04./ V


21/35

2/

In order to measure the alternating currentwith

the dArsonval meter movement, we must rectifythe alternating current by use of diode rectier.

Figure 2.2.5is the DC voltmeter circuit modiedto measure AC voltage.

The diode, assume to be ideal diode, has no eecton the oeration of the circuit . !or e"amle if the 10 V sine-wave inputis fed as

the source of the circuit, the voltage across themeter movement is #ust the ositive half$cycle of

the sine wave due to the rectifying eect of thediode.

. .Movement with Half-WaveRectication.

2.2.5 D! "oltmeter !ircuitMo#ie# to Measure A!

"oltage.


22/35

22

The full$wave rectier rovide higher sensitivityrating comare to the half$wave rectier.

%ridge tye rectier is the most commonly used,Figure 2.2.$.

. . rsonva e erMovement with Full-WaveRectication.

Figure2.2.$ Full Wave %ri#ge Rectier &se# in A!"oltmeter !ircuit.

!ont#


23/35

23

'(eration) &a' During the ositive half cycle &re#arrow', currents (ows

through diodeD2, through the meter movement from ositive tonegative, and through diodeD3.

$ The olarities in circles on the transformer secondary are for the

ositive half cycle.$ )ince current (ows through the meter movement on both halfcycles, we can e"ect the de(ection of the ointer to be greater thanwith the half wave cycle.

$ If the de(ection remains the same, the instrument using full waverectication will have a greater sensitivity.

&b' *ise$versa for the negative half cycle &blue arrow'.

!ont#*


24/35

DEE2023 SEMICONDUCTOR DEVICES 2+

2. DIODE IN OTHER E/ECTRONICS CIRCUIT

A00/ICATIONS

2.*.1 C!I//#($irst clipper circuit

a. Diode is for'ard !iased d)ri"g %ositi$e ha&f c(c&e.This ma-es the %ositi$e %ote"tia& 0.4V


25/35


!. O)t%)t s'i"gs from 0.4V %ositi$e to 0V "egati$e

2.*.1 C!I//#(

$irst clipper circuit - Cont.


26/35

DEE2023 SEMICONDUCTOR DEVICES2:

2.*.1 C!I//#(

Second clipper circuita. Diode is for'ard !iased d)ri"g %ositi$e ha&f c(c&e.This ma-es the "egati$e %ote"tia& 0.4V


27/35


!. O)t%)t s'i"gs from 2+V %ositi$e to 0.4V "egati$e

2.*.1 C!I//#(

Second clipper circuit - Cont.


28/35

DEE2023 SEMICONDUCTOR DEVICES2=

2.*.1 C!I//#(

Third clipper circuita. Si"ce diodes are i" series* each !ra"ch 'i&& dro% 0.4V G 0.4V

/.+V


29/35

DEE2023 SEMICONDUCTOR DEVICES 2@

!. O)t%)t s'i"gs from G/.+V %ositi$e to /.+V"egati$e

2.*.1 C!I//#(

Third clipper circuit - Cont.


30/35



A00/ICATIONS

2.*.1 C!A/#($irst clamper circuit

a. DC %ote"tia& is %- B 0.4V /+.3V This !ecomes the ?ero refere"ce &i"e for the #C* so it 'i&& go

/V a!o$e a"d /V !e&o' this &i"e


31/35

DEE2023 SEMICONDUCTOR DEVICES 3/

!. O)t%)t s'i"gs from [email protected] %ositi$e to 0.4V"egati$e

2.*.1 C!A/#(

$irst clamper circuit - Cont.


32/35



A00/ICATIONS

2.*.1 C!A/#(Second clamper circuit

a. DC %ote"tia& is %- B 0.4V [email protected] This !ecomes the ?ero refere"ce &i"e for the #C* so it 'i&& go

30V a!o$e a"d 30V !e&o' this &i"e


33/35


!. O)t%)t s'i"gs from G0.4V %ositi$e to @.3V"egati$e

2.*.1 C!A/#(

Second clamper circuit - Cont.


34/35

DEE2023 SEMICONDUCTOR DEVICES 3+


A00/ICATIONS

2.*.1 C!A/#(

Third clamper circuit

a. This o"e charges the ca%acitor d)ri"g the %ositi$e a&ter"atio"*a"d this 'i&& the" discharge d)ri"g the "egati$e a&ter"atio".

!. This ma-es the o)t%)t at ma8im)m a straight &i"e of +0V 2V%-6c. 7o'e$er* si"ce the diode is "ot %erfect 'e "eed to )se the first

a%%ro8imatio" sim%&ified diode6 This mea"s 'e "eed to s)!tract 0.4V for the o"e diode thatcharges the ca%acitor [email protected]

#"d &est 'e forget* s)!tract the %ote"tia& for the seco"ddiode as 'e&& 3=.:V6


35/35

DEE2023 SEMICONDUCTOR DEVICES

!. O)t%)t is %)&sati"g 'a$e ri%%&e6 that rises to a ma8im)m%ote"tia& of [email protected] a"d desce"ds to a mi"im)m %ote"tia& of3=.:V

2.*.1 C!A/#(

Third clamper circuit - Cont.

diod rectifier

Documents