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Operational amplifer and their application
Voltage ollower Voltage ollower with an ideal operational
amplifer simply gives inputvoltage equals output voltage . Input
impedance o operational amplifer is
very high giving eective isolation o output rom signal source
.
Procedure:-
!" connect the networ# as shown
$ni#et %&!'()!&*!&
+a, partner-$yush oshi %&!'))*&'&
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%" /easure the output o signal generator
directly on (0O and ad1ust it to ,e %V pea# to
pea#.
*" /easure the output o signal generator across
''.2ohm resistance or input voltage %V pea# topea# output
voltage is pea# to pea#.
2" disconnect the resistance and connect signal
generator output to input o circuit shown in fg.
and measured output or input voltage %V pea# to
pea#.
O,servation:-
a" 3or input voltage %V pea# to pea# outputcurve is as shown
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," Output o signal generator across resistance
o
''.2 ohm is as shown
c" $ter disconnecting resistor and ma#ing circuit
as mention a,ove output curve is
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Inverting amplifer :-
4heory:-
Inverting amplifer is special case o dierential
amplifer in which circuits non-inverting input V%is grounded and
inverting input V! is identifed
with Vin a,ove .
Vout 5 -0Vin"60in
Procedure:-
!" 7et up circuit as shown in fg.
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3or gain o !& circuit is as ,elow
3or gain o '& circuit is as ,elow
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%" (hoose resistance 0! and 0 to achieve gains
!& and
'&.
*" Veriy operation at dierent requencies say !
#89 and 2& #89 .
O,servation:-
a" 3or resistors o 2. #ohm and 2
#ohm and requency o !#89 output
curve is as ,elow
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3or 2& #89 requency output curve is asshown
," 3or resistors o 2. #ohm and %%ohm
$nd requency ! #89 output curve is as
shown
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3or requency o 2& #89 output is as
,elow
;on-inverting amplifer
4heory:
4he input signal is applied to positive or non-inverting input
terminal o operational amplifer
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and a portion o output signal is ed ,ac# to
negative input terminal.
Input voltage and output voltage are related asV& 5
0!Vin60!
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3or gain o '& circuit is as shown ,elow
%" (hoose resistances 0 and 0! to achieve gains
!& and '&.
*" Veriy operation or dierent requencies and,y plotting output
vs input curve
Voltage gain 5 !< 060!
O,servation:-
a" 3or resistors o 2. #ohm and 2 #ohm
and requency o ! #89 output is as shown
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3or requency o 2& #89 output is as shown
," 3or resistors o 2. #ohm and %%& #ohm
resistors and requency o ! #89 output is as
shown
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3or requency o 2& #89 output is as shown
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0eal lie applications:-
!" Operational amplifers are used as audio and
video preamplifers and ,uers .
%"4hey are also used as voltage regulator andcurrent regulator
.
*"4hey are used as flters = digital to analog
convertor = analog to digital convertor .
2"Operational amplifers are also used as charge
amplifer = oscillators and waveorm generators.
