Clamper Circuits

Ritan Barua Clamper circuits Presentation

1. Digital Electronics and Pulse Techniques (EEE-3205)
Clamper Circuits
Outline
What are clamper circuits?
Working of clamper circuits
Types of clamper circuits
Applications of clamper circuits
Discussion
Why capacitor is used in clamping circuit(Group work)
Conclusion

2. What are clamper circuits?
•Aclamperisanelectroniccircuitthatfixeseitherthepositiveorthenegativepeak
excursionsofasignaltoadefinedvaluebyshiftingitsDCvalue.
•Theclampingnetworkisonethatwill"clamp"asignaltoadifferentdclevel.
•Atypicalclamperismadeupofacapacitor,diode,andresistor.Someclamperscontain
anextraelementcalledDCbattery.Theresistorsandcapacitorsareusedintheclamper
circuittomaintainanalteredDClevelattheclamperoutput.Theclamperisalsoreferred
toasaDCrestorer,clampedcapacitors,orACsignallevelshifter.
•Clampingcircuitswerecommoninanalogtelevisionreceivers.ThesesetshaveaDC
restorercircuit,whichreturnsthevoltageofthevideosignalduringthe'backporch'ofthe
lineblanking(retrace)periodto0V.Lowfrequencyinterference,especiallypowerline
hum,inducedontothesignalspoilstherenderingoftheimage,andinextremecases
causesthesettolosesynchronization.Thisinterferencecanbeeffectivelyremovedvia
thismethod

3. Working of Clamper Circuit
During the first negative phase of the AC input voltage, the capacitor in a positive
clamper circuit charges rapidly. As Vin becomes positive, the capacitor serves as a
voltage doubler; since it has stored the equivalent of Vin during the negative cycle, it
provides nearly that voltage during the positive cycle. This essentially doubles the
voltage seen by the load. As Vin becomes negative, the capacitor acts as a battery of
the same voltage of Vin. The voltage source and the capacitor counteract each other,
resulting in a net voltage of zero as seen by the load.

4. Types of clamper circuits
The clamper circuits are of the following types:
Positiveclampers.
Negativeclampers.
Biasedclampers.

5. Applications of Clampers Circuits
oThe complex transmitter and receiver circuitry of television clamper is used as a
base line stabilizer to define sections of the luminance signals to preset levels.
oClampers are also called as direct current restorers as they clamp the wave forms
to a fixed DC potential.
oThese are frequently used in test equipment, sonar and radar systems.
oFor the protection of the amplifiers from large errant signals clampers are used.
oClampers can be used for removing the distortions
oFor improving the overdrive recovery time clampers are used.
oClampers can be used as voltage doublers or voltage multipliers.

6. Discussion
Q/A

7. Group Work
Why Capacitor is used in clamper circuit?

8. Conclusion
Q/A

9. Following Lecture
Positive clampers & Negative clampers