3.4.Clipper,clamper,peak detector.ppt

Linear Integrated Circuits
Unit - II
Clipper, Clamper, Peak Detector,
Sample and Hold Circuit
Annexure – I Notes of Lesson

Objectives
 Clipper
 Clamper
 Peak Detector
 Sample and Hold Circuit
 Applications

General Objective:
 To understand the operation of clipper, clamper and
peak detector along with their applications

Specific Objective
 Differentiate positive and negative clipper. (S,E)

CLIPPER
 A circuit which is used to clip off certain portions of the
input voltage to get desired output
 A rectifier diode may be used to clip off.
 The clipping level is determined by the reference voltage
Vref
 Types
 Positive Clipper Circuit
• Removes some positive part from the input to
produce the output
 Negative Clipper Circuit
• Removes some negative part from the input to
produce the output

Positive Clipper
if Vi<=Vref, Vo= Vi
&
if Vi>Vref, Vo= Vref

Negative Clipper
 if Vi>=Vref, Vo= Vi
 if Vi<Vref, Vo= Vref

Specific Objective
 Exemplify the working of negative clamper circuit. (E)

CLAMPER
 The circuit used to add a desired dc level to the output
voltage
 This circuit clamps the peak of the input waveform and
hence called as Peak Clamper
 Also known as dc inserter or dc restorer.
 Types
 Positive Clamper
• If the clamped dc level is positive
 Negative Clamper
• If the clamped dc level is negative

Positive Clamper
Input and output waveform with
+Vref
Vo= Vref+Vi+Vm
 Negative clamping is
obtained by reversing the
diode and using -Vref

Formative Assessment
1. The circuit which is used to insert a DC level at the
output is called______________
a)clipper b)clamper c)peak detector
d)Schmitt trigger
2. The circuit which is used to store the highest value of the
input signal is______________
a)comparator b)clipper c)peak detector
d)multivibrator
3.When alarge sine wave drives a Schmitt trigger, the
output is a
a)rectangular wave b)triangular wave
c)rectified sine wave d)series of ramp

4.___________ circuit is very useful in digital interfacing,
analog to digital and pulse code modulation systems.
a)clipper b)clamper c)peak detector
d)Sample and hold circuit
5. A positive clipper can be converted into a negative
clipper by simply
a) reversing the diode only b) changing the
polarity of Vref
c) both a and b d) reversing the input

Specific Objective
 Illustrate the basic principle of peak detector circuit. (S)

PEAK DETECTOR
 To compute the peak value of
the input
 If Vi>VC , then D is forward
biased , Vo=Vi
 If Vi<VC , then D is reverse
biased, Vo=VC
 Capacitor voltage can be
made zero by connecting switch
across the capacitor
 Reversing the diode, circuit holds
the most negative voltage of
the signal
Positive Peak Detector

SAMPLE AND HOLD CIRCUIT
 Samples an input signal and holds on to its last sampled
value until the input is sampled again
 Analog signal Vi to be sampled is applied to the drain of E-
MOSFET
 Control voltage Vc is applied to its gate
 When Vc is positive, Vo =Vi
 When Vc is zero, Vo=Vc, capacitor holds the voltage across
it
 Sample Period:
 Ts, the time during which the voltage across the
capacitor is equal to input voltage
 Hold Period:
 TH, the time during which the voltage across the capacitor
is held constant

Applications
 Clamper
Television receivers
 Peak Detector
Test and measurement instrumentation
Amplitude modulation communication
 Sample and Hold Circuit
Digital interfacing
Analog to digital conversion
Pulse Code modulation systems

Stimulating Questions:
 1. Specify the necessity of sample and hold circuit.
 2. List some of the performance parameters of
sample and hold circuit.
22

MIND MAP
Clip off unwanted
portion of Output
voltage
Removes
some
positive part
from the
input
Removes
some
negative
part from
the input

Summary
 Clipper
 Circuit used to clip off certain portions of the input
voltage
 Positive Clipper
• Removes some positive part from the input
 Negative Clipper
• Removes some negative part from the input

3.4.Clipper,clamper,peak detector.ppt

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3.4.Clipper,clamper,peak detector.ppt