Advantages of The Op-Amp Precision Rectifier Circuit
The advantages of the op-amp precision rectifier circuit over a simple diode rectifier are
1) No diode voltage drop between input and output
2)The ability to rectify very small voltages (less than the typical 0.7 V diode forward voltage drop)
3) Amplification, if required
4) Low output impedance
Items (1) and (2) indicate
Saturation of The Op-Amp Output
Output Saturation
While the input waveform is in its negative half-cycle, the output of the op-amp in Fig.7-1(a) is saturated in a negative direction.
Some time is required to get the op-amp out of saturation and this will limit thr frequency response of the circuit.
For high frequency performance, a nonsaturating precision rectifier circuit must be used.