On Wed, 09 Nov 2011 20:49:28 +0000 (GMT), Stuart
wrote:

In article ,
Don Pearce wrote:
Provides a Vcc/2 local "ground" so I can use these op amps with a single
supply voltage.

More useful to let it oscillate as a square wave generator at 100kHz
or so, and rectify the output into a negative 15V rail. That way you
can run the op amps the way they are meant to be run.

KISS

Exactly. Much easier than all these halved supplies, coupling caps and
multiple grounds.

d