Clamper Using Opamp Nptel
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Lecture - 17: Applications of Operational Amplifiers Clampers: Fig. 3, shows an active positive clamper circuit. Fig. 3 The first negative half cycle produces a positive OPAMP output, which turns ON the diode. This capacitor charges to the peak of the input with the polarity shown in fig. 3. Just beyond the negative peak the diode turns off, the feedback loop opens, and the virtual ground is lost. Therefore, v out = v in + V P Since V P is being added to a sinusoidal voltage, the final output waveform is shifted positively through V P volts. The output wave form swing from 0 to 2V P as shows in fig. 4. Again the reduction of the diode-offset voltage allows clamping with low-level inputs. During most of the cycle, the OPAMP operates in negative saturation. Right at the negative input peak, the OPAMP produces a sharp positive going pulse that replaces any change lost by the clamping capacitor between negative input peaks. Fig. 4 GOTO >> 1 || 2 || 3 || Home Lecture 17 http://nptel.ac.in/courses/Webcourse-contents/IIT-ROORKEE/Analog cir... 1 of 1 5/21/2014 6:18 PM
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Clamper Using Opamp
Transcript of Clamper Using Opamp Nptel
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Lecture - 17: Applications of Operational Amplifiers
Clampers:
Fig. 3, shows an active positive clamper circuit.
Fig. 3
The first negative half cycle produces a positive OPAMP output, which turns ON the diode. This capacitor charges tothe peak of the input with the polarity shown in fig. 3. Just beyond the negative peak the diode turns off, the feedbackloop opens, and the virtual ground is lost. Therefore,
vout = vin + VP
Since VP is being added to a sinusoidal voltage, the final output waveform is shifted positively through VP volts. The
output wave form swing from 0 to 2VP as shows in fig. 4. Again the reduction of the diode-offset voltage allowsclamping with low-level inputs.
During most of the cycle, the OPAMP operates in negative saturation. Right at the negative input peak, the OPAMPproduces a sharp positive going pulse that replaces any change lost by the clamping capacitor between negativeinput peaks.
Fig. 4
GOTO >> 1 || 2 || 3 || Home
Lecture 17 http://nptel.ac.in/courses/Webcourse-contents/IIT-ROORKEE/Analog cir...
1 of 1 5/21/2014 6:18 PM
