Hi Kai,

Thank you very much for your informative reply.

Have a look at datasheet of OPA27/37 for instance and you will see, that also antiparallel diodes can be found between inverting and noninverting input of this OPamp

I have downloaded the datasheet and will read go through it.

Thanks for wiping of the 33pF mystry.

Don't forget this 1kOhm resistor! As it is mounted in series to both 20kOhm resistors, it acts like a 2kOhm resistor, to be added to each 20kOhm, giving 22kOhm!

You are right kai, I tested the circuit using Circuit Maker 2000 simulator and with 20K values the output is rectified with same amplitude as input but with 22K values it is 90% of the input in amplituded.


If I am right The scaling of the output can be done by using a variable resistor in place of the extreme right side 22K resistor i.e TLC277.

Thanks & Regards,
Prahlad Purohit