II) PEAK DETECTORS
Precision Half-Wave Rectifier Peak Detector
2) Voltage Follower Peak Detector (Positive Peak Follower and Hold)
A peak detector monitors an input signal and holds its output voltage at the peak level of the input.
This is achieved by charging a capacitor to the peak voltage level.
A very simple peak detector can be constructed by the use of a diode and capacitor as illustrated in Fig.7-11(a).
When the input voltage (Vi) increases to Vp, the capacitor is charged to (Vp-VF).
When Vi falls below Vp, D1 is reverse biased and C1 retains its charge.