Andre Abelian wrote:
>
> Quentin,
>
> In the schematic I do not understand the purpose of Q1
> I will appreciate if some one can  explain it.
>
> Andre
I should have included this in my last email as well, as it is not my
design:
http://home.hiwaay.net/~mjn/theory.htm
The first paragraph will explain to you how it works.

Quentin