Re: How asymmetrical is an op-amp supply allowed to be?



Lostgallifreyan wrote:
"I.F." <dai.ode@xxxxxxxxxxxx> wrote in
news:hPP4g.9073$l91.8093@xxxxxxxxxxxxxxxxxxxx:


"Lostgallifreyan" <no-one@xxxxxxxxxxx> wrote in message
news:Xns97B4CFF7CA316lostgallifreyangmail@xxxxxxxxxxxxxxxx
How asymmetrical is a dual rail op-amp supply allowed to be?

Some op-amps are designed to run on single supply only - you can't
get much more asymmetric than that! - It really depends what your
application is, for most purposes good symmetry optimises the maximum
output swing without asymmetric clipping.




Thankyou. I want asymmetry to get true zero offset that isn't
possible with single-rail supply. If I feed a +/- 18V max-rated
op-amp with near to max voltage, and set the ground close to the
negative rail, maybe just a half volt higher, could I get the output
to swing close to the other rail? Or is it fatal to the opamp to make
its output go further than 18V above my ground, wherever I set it?

Your op-amp only has a +ve and -ve supply connection. Therefore
it has no idea where GND is except what you tell it by the circuit
config.

--
Graham W http://www.gcw.org.uk/ PGM-FI page updated, Graphics Tutorial
WIMBORNE http://www.wessex-astro-society.freeserve.co.uk/ Wessex
Dorset UK Astro Society's Web pages, Info, Meeting Dates, Sites & Maps
Change 'news' to 'sewn' in my Reply address to avoid my spam filter.
.