9. 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
13. 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
14. Positive Clamper
Input and output waveform with
+Vref
Vo= Vref+Vi+Vm
Negative clamping is
obtained by reversing the
diode and using -Vref
15. 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
16. 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
18. 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
20. 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
21. 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
22. Stimulating Questions:
1. Specify the necessity of sample and hold circuit.
2. List some of the performance parameters of
sample and hold circuit.
22
27. MIND MAP
Clip off unwanted
portion of Output
voltage
Removes
some
positive part
from the
input
Removes
some
negative
part from
the input
28. 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