operational amplifiers and basic applicationsclass.ece.iastate.edu/ee230/lectures/ee 230 lecture 10...
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EE 230Lecture 10
Operational Amplifiers and Basic Applications
Review from last time
OUTIN
Aβ1AAFB +
=
β1AFB≅
Review from last time
Feedback significantly and simultaneously improves most parameters of interest by a factor of about 1+Aβ
Feedback properties is the major driving factor behind the evolution and use of operational amplifiers
Review from last time
Feedback significantly and simultaneously improves most parameters of interest by a factor of about 1+Aβ
Review from last time
For a VCVS Op Amp
Review from last time
2
1
OUT
( )12OUT VVAV −=
For a VCVS Op Amp
Consider the following circuit
AV
Consider the following circuit
This is exactly the feedback architecture in the case where the input and output variables are voltages
This is a voltage feedback amplifier
AV
Consider the following circuit
Aβ1AAFB +
=
1
2FB R
Rβ1A +=≅ 1
VAA =
AV
21
1
RRRβ+
=
1
2
IN
OUTFB R
RV
VA +≅= 1
Basic Noninverting Amplifier
Redraw this feedback circuit
1
2
IN
OUTFB R
RV
VA +≅= 1