CLAMPING CIRCUITES,CLIPPER & PEAK DETECTORS Dr. C. Saritha, Lecturer in Electronics S.S.B.N P.G COLLEGE, ANANTAPUR

OVERVIEW  INTRODUCTION  DEFINATIONS  CIRCUIT DIAGRAMS  WAVEFORMS  CONCLUSION

Some of the non linear function circuits are :  CLAMPERS  CLIPPERS  PEAK DETECTORS INTRODUCTION

CLAMPING CIRCUITS  The clamping circuits in general, designed “clamp” the top or bottom of a waveform.  Fixed d.c. level, which may be zero, while preserving its shape and amplitude  The distinguishing feature of a clamper is that is it adjusts the d.c. level without needing to know the exact waveform.

Zero volts-waveforms

CLAMPING CIRCUITS:

Waveforms :

Operation of the circuit : input voltage v i = v m sin ω t and v ref Interval 0 ≤ ω t ≤ π : V i is positive, V d is negative V 0 is negative the diode is reverse biased. No current flows through the capacitor i.e. it is not charged. Interval π ≤ ω t ≤ 3 π/2 : V i is negative V 0 is positive. The diode conducts and the NV terminal of the op amp behaves as virtual ground. The capacitor c 1 gets charged with point A at a potential higher than that of point be the capacitor gets charged to the peak value V m of the input voltage.

Interval ω t > 3π/2 : V d = - (V m + V i ) = -V m (1+sin ωt ) And diode D is OFF. As a result the output voltage. V 0 = - V d = V m (1+sin ωt ) Reference voltage the capacitor gets charged to ( V m + v ref ) the output voltage. V 0 = V m sin ωt + ( V m + v ref )

Examples : V m = 10 v and V ref = 5 v V 0 = 10 sin ωt = 10 sin ωt + 15

Waveforms for + v ref and – v ref :

CLIPPER  Clipper are circuits which can clipp off a portion of the input waveform without distorting the rest of the waveform.  Clipping circuits are also refer limiter amplitude selectors or slicers.

POSITIVE CLIPPER : Precession diode which can be used to slice off a portion of the positive half of the input signal. The level at which clipping is done is determined by the reference voltage.

Positive clipper :

Positive clipper waveforms :

NEGATIVE CLIPPER : Reversed and the reference voltage the resulting circuit is a negative clipper circuit. it clips OFF the negative region of the input signal waveform below the reference voltage.

Negative clipper circuit :

Negative clipper waveforms :

PEAK DETECTORS Detector : The maximum value is called detector Peak detectors : Peak detectors ate electronic circuits that track the input signal faithfully until it detects a peak and holds that value until a new, Larger peak is detected.

Basic peak detector : The diode allows un directional current to charge the capacitor. The capacitor stories the charge and acts as a voltage memory. It holds the peak value of the input voltage. To detect a peak, S 1 has to be closed and S 2 open. To hold the peak value both the switches should be open. To reset the circuit, S 1 has to be opened and S 2 closed.

Basic peak detector :

Peak detector waveform :

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