On Tue, 19 Nov 2002, Olin Lathrop wrote:

> >   Old fashion: a npn transistor or an open collector gate with 15V Vce (
> > unfortunately the open drain ra4 style is out of voltage spec ) which
> > control a power NPN ( darlinghton if necessary ). A resistor across the
> BC
> > of power transistor keep the transistor on, the open colector
> controlling the
> > base of the same transistor shut down the whole kk when is on.
> > Everything can be replaced with a 4 terminal controlled 12V stab with
> > reference adjustment floated with 1V upper the ground using a
> > simple resistor.
>
> I don't like this because it results in higher voltage drop when on and
> will require some current just to keep off.
>
  True, nothing it's perfect.
  For 1A load, and a darlington ( let say h21e = 100 ) will be 10mA
on command. It's not very huge...

Have a nice day, mine it's over.

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