[sdiy] rev log voltage ic??

[Ken Stone]

>If not, does everyone just use a transistor on the feedback of an op amp and
>gound the base to get the log voltage?

One can do this, but the circuit is ultra sensitive to thermal variation, so
one would either need to heat the transistor to a constant temperature well
above ambient, or use a more complex circuit where these effects have been
compensated for.

Ken
_______________________________________________________________________
Ken Stone   sasami at hotkey.net.au or sasami at cgs.synth.net
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>