Positive Peak Detector with Buffered Output
Op Amplifiers circuits

Positive Peak Detector with Buffered Output

By Robert J. Widlar


The peak detector is similar in many respects to the sample-and-hold circuit.

The peak detector in Figure 1 is similar in many respects to the sample-and-hold circuit. A diode is used in place of the sampling switch. Connected as shown, it will conduct whenever the input is greater than the output, so the output will be equal to the peak value of the input voltage. In this case, an LM102 is used as a buffer for the storage capacitor, giving low drift along with a low output resistance.

Figure 1. Positive Peak Detector with Buffered Output
Figure 1. Positive Peak Detector with Buffered Output

As with the sample and hold, the differential input voltage range of the LM101 permits differences between the input and output voltages when the circuit is holding.

4140 08 December 2007

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