[sdiy] Change response from Lin to Log to Lin to Exp?

[Justin Owen]

-----Original Message-----
From: Tim Parkhurst [tim.parkhurst at gmail.com]
Received: 09.12.2011 21:41:13
To: Justin Owen
Cc: SDIY List
Subject: Re: [sdiy] Change response from Lin to Log to Lin to Exp?


>> http://www.sdiy.org/juz/vca_comparison_03.jpg

>That offset looks more like it might be the ~0.6V voltage drop across
the transistor. Maybe you need to bias the base 0.6V in the opposite
direction?

Yup, completely right - and completely obvious once it was pointed out to me!

Setting the Base Bias to 1V and adjusting the values of the resistor from the Bias V to the Base and the resistor from the CV to the Base got me within an average of 0.05V error compared to the curve of the 2164.

Nice. Thanks.

J