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Voltage Amplife

CREATED BY: BINTANG MOHAMMADNPM: 14!!4"#$1

ME%ATRONI%A & "

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Co'te't(

• I'tro)*+tio'• Operatio'al Amplifer

• I)eal Op Amp

•

 I',erti'g Amplifer• No'i',erti'g Amplifer

• -ampel Pro.lem a') -ol*tio'

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I'tro)*+tio'

+

-

 Non-inverting input

Positive voltage supply

 Negative voltage supply

O

Symbol

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Operatio'al Amplifer / Op Am

The Op Amp Model+

-Inverting input

 Non-inverting input

 Rin

v+

v-

+-

 A(v+

-v-)

 Ro

• The op amp is designed to sense the difference between the voltage

signals applied to the two input terminals and then multiply it by a

gain factor A such that the voltage at the output terminal is A(v+-v-)

• The voltage gain A is very large (practically infinite) The gain A is

often referred to as the differential gain or open-loop gain

• The input resistance Rin is very large (practically infinite) The output

resistance Ro is very small (practically !ero)

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I)eal Op Amp

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Voltage AmpliferI',erti'g Co'fg*ratio'

Ge'eral E*atio'(:i1 2 ,i'3R1i 2 i1,o 2 &iR  2 &,i'R3R1

A, 2 R3R1    2 R13R

 T5e (ame a((*mptio'(f') t5e e*atio'( 6or t'o'i',erti'g +o'fg*raal(o *(e) 6or t5e i',er+o'fg*ratio'7

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I'p*t a') O*tp*t Re(i(ta'+eI)eall89 t5e i'p*t re(i(ta'+e 6or t5i( +o'fg*ratio' i( e*i,ale't to R17

Hoe,er9 t5e a+t*al ,al*e o6 t5e i'p*t re(i(ta'+e i( gi,e' .8 t5e 6olloi'g6orm*la:

Ri' 2 R1 ; R

  1 ; AO<I)eall89 t5e o*tp*t re(i(ta'+e i( =ero9 .*t t5e 6orm*la .elo gi,e( a morea++*rate ,al*e:

Ro 2 Ro

  1 ; AOere't 6rom t5e e*atio' *(e)

  R1 ; R o' t5e pre,io*( (li)e9 5i+5 +a' .e +o'6*(i'g7

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I',erti'g Co'fg*ratio'E?ample

Gi,e': ,i' 2 7! V9

R1 2 " @ 9 AO<

Ri' 2 M  9 R

i'): ,o 9 i 9 A, 9  

-ol*tio':

,o 2 &iR  2 &,i'R3R1 2 &/7!"903" 2 1" V

i 2 i1  2 ,i'3R1  2 1 3 " 2 7 mA

A, 2 R3R1  2 "9 3 " 2 1   2 R13R  2 " 3 "9 2 71

Ri' 2 R1 ; R 2 " ; "9 2 "97

  1 ; AO<   1 ; 49

Ro 2 Ro 2 !  2 17!$ m

  1 ; AO

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No'i',erti'g Amplifer

,i) 2 ,o3AO<

A((*mi'g AO

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 T5e +lo(e)&loop ,oltage gai' i( (8m.oli=e) .8 A, a') i( 6o*') to .e:  A, 2 ,o  2 R ; 1

,i'  R1

 T5e origi'al +lo(e) loop gai' e*atio' i(:

  A, 2 A 2 AO<

  1 ; AO

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I'p*t a') O*tp*t Re(i(ta'+eI)eall89 t5e i'p*t re(i(ta'+e 6or t5i( +o'fg*ratio' i( i'f'it89 .*t t5e a

+lo(er pre)i+tio' o6 t5e a+t*al i'p*t re(i(ta'+e +a' .e 6o*') it5 t5e6olloi'g 6orm*la:

Ri' 2 Ri' /1 ; AO

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No'i',erti'g Co'fg*ratio' E?ample

-ol*tio':

,o 2 ,i' ; ,i'R  2 7! ; 7!"?1  2 !7! V i 2 ,i' 2 7! 2 7F

mA

 R1 " R1  "

A, 2 R ; 1 2 "?1 ; 1 2 11   2 1 2 1 2 #7#?1&F

  R1 " AO