[sdiy] Guard Rings

[Harry Bissell]

right. The flip side is that the guard ring might be best driven from the emitter anyway, even including the drop. If it were attached to the FET source, it would also be connected to the transistor base and might be an antenna...  As it is, it would guarantee that any board leakage would have only a .7V drop to discharge the hold cap with.

In classic form this would have been an opamp follower with only the offset voltage across
the guard ring and the hold cap...

H^) harry



----- Original Message -----
From: Ian Fritz <ijfritz at comcast.net>
To: Veronica Merryfield <veronica.merryfield at shaw.ca>, Dave Manley <dlmanley at sonic.net>
Cc: synth-diy at dropmix.xs4all.nl
Sent: Fri, 05 Nov 2010 11:32:06 -0400 (EDT)
Subject: Re: [sdiy] Guard Rings

At 01:32 AM 11/5/2010, Veronica Merryfield wrote:
> > Thanks, it's an emitter follower isn't it?  Guess it's time to go back 
> to my
> > basic transistor circuits books for a review.  :-0
>
>Yes, or a common collector.

Hmmm...Looks like I'll have to review this too.  Aren't you calculating the 
AC gain? Doesn't the emitter have to be DC biased one diode drop below the 
base?

Ian 

_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy

-- 
Harry Bissell & Nora Abdullah 4eva