Oops. Sorry, i meant Martin, obviously.

2011/6/22 Roman Haefeli <reduzent@gmail.com>
On Wed, 2011-06-22 at 15:06 +0200, Pierre Massat wrote:
> Thank you all for your advice.
>
> @Roman : what type of op-amp do you use?

I guess, it was Martin Peach who suggested using an op-amp. However, I
think many common ones will do.

Roman