David Beierl wrote:

> >$10 Radio Shack volt meter, do I need something more accurate?
>
> You need a scope or meter with 10 megohms input impedance.  Most digital
> meters have this, some of the cheapest do not.  Very few analog meters do.
>
> david

But then of course digital meters usually don't update quickly enough to
follow the O2 voltage. ;-(

Larry A.