Non linear resistive attenuator - linear to exponential converter

Hi Folks, I built this circuit as a fun way to brute force an approximate linear voltage to exponential current conversion by playing with the V-I characteristics of diodes. It worked out, but can someone please help me understand how to take the exponential current going through the ammeter in this circuit and convert that to an exponential voltage that I can then send through a bufFer to create a low impedance exponential voltage signal? I tried adding a resistor to ground at the ammeter but that messes up the nonlinear current output. Also tried a transistor based current buffer but I think I hooked it up incorrectly. Thanks.

published 9 years ago