UNIT-II
Applications of Operational
Amplifier
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Inverting Amplifier (or) Scale Changer
Rf
VOUT V IN
R1
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Non-Inverting Amplifier
Rf
VOUT VIN 1
R1
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Voltage follower
Rf
VOUT VIN 1
R1
If R1 and Rf = 0
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Summing Amplifier
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Differentiator
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Differential amplifier
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Instrumentation Amplifier
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Instrumentation Amplifier
In a number of industrial and consumer
applications, the measurement of physical quantities is
usually done with the help of transducers. The output of
transducer has to be amplified So that it can drive the
indicator or display system. This function is performed
by an instrumentation amplifier
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Features of instrumentation amplifier
1. high gain accuracy
2. high CMRR
3. high gain stability with low temperature co-
efficient
4. low dc offset
5. low output impedance
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Comparator
A comparator is a circuit which compares
a signal voltage applied at one input of an
op- amp with a known reference voltage at
the other input. It is an open loop op - amp
with output + Vsat
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Applications of comparator
1. Zero crossing detector
2. Window detector
3. Time marker generator
4. Phase detector
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Schmitt trigger
Schmitt trigger is a regenerative comparator. It
converts sinusoidal input into a square wave output.
The output of Schmitt trigger swings between upper
and lower threshold voltages, which are the
reference voltages of the input waveform
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Multivibrator
Multivibrators are a group of regenerative circuits
that are used extensively in timing applications. It is a
wave shaping circuit which gives symmetric or
asymmetric square output. It has two states either
stable or quasi- stable depending on the type of
multivibrator
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Filter
Filter is a frequency selective circuit that passes
signal of specified Band of frequencies and attenuates
the signals of frequencies outside the band
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Active filters
Active filters used op- amp as the active
element and resistors and capacitors as passive
elements. By enclosing a capacitor in the feed back loop
, inductor less active filters can be obtained
some commonly used active filters
1. Low pass filter
2. High pass filter
3. Band pass filter
4. Band reject filter
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Precision rectifier
HWR:
50
FWR:
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