7812 and 7805 for powering a stamp and 2 IC''s
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Posts: 46,084
No, I am sure that we both understand that a 7805 generates 5v and a
7812 12v. What I was trying to point out, and to answer his original
question, was that the regulator can provide 5v (or 12v) over a very
wide range of currents. He had originally asked if he was drawing too
little current for it to provide propper regulation.
I was simply trying to keep the discussion with the tread and not
actually answering or commenting directly on your post. Sorry for the
confusion.
Phil
--- In basicstamps@y..., Kevin Olalde <kolalde@h...> wrote:
> I'm not following you here. Are you pointing out to me that the
7805 doesn't
> generate 12V (if so, I understand that). Tim's original post didn't
give any
> reason why 12V was needed, so I was wondering, out loud, why he
needed the two
> voltages?
>
> He's since posted that he's using a 12V relay, so now the other
voltage makes
> more sense to me.
>
> Kevin
>
> Phil Keller wrote:
> >
> > The data sheet that I have for a 78MxxC/LM340 lists the Vo at 4.8
to
> > 5.2 at 5mA < Io < 1A.
> >
> > I can forward the data-sheet if you would like (or go to the
> > National Semiconductor site and down load it.)
> >
> > Phil
> >
> > --- In basicstamps@y..., Kevin Olalde <kolalde@h...> wrote:
> > > Can the 7812 be skipped? I'm not saying that's what the
original
> > problem is,
> > > just wondering why the whole curcuit can't just be run from the
same
> > 7805 (or is
> > > there a specific need for 12V)?
> > >
> > > Kevin
> > >
7812 12v. What I was trying to point out, and to answer his original
question, was that the regulator can provide 5v (or 12v) over a very
wide range of currents. He had originally asked if he was drawing too
little current for it to provide propper regulation.
I was simply trying to keep the discussion with the tread and not
actually answering or commenting directly on your post. Sorry for the
confusion.
Phil
--- In basicstamps@y..., Kevin Olalde <kolalde@h...> wrote:
> I'm not following you here. Are you pointing out to me that the
7805 doesn't
> generate 12V (if so, I understand that). Tim's original post didn't
give any
> reason why 12V was needed, so I was wondering, out loud, why he
needed the two
> voltages?
>
> He's since posted that he's using a 12V relay, so now the other
voltage makes
> more sense to me.
>
> Kevin
>
> Phil Keller wrote:
> >
> > The data sheet that I have for a 78MxxC/LM340 lists the Vo at 4.8
to
> > 5.2 at 5mA < Io < 1A.
> >
> > I can forward the data-sheet if you would like (or go to the
> > National Semiconductor site and down load it.)
> >
> > Phil
> >
> > --- In basicstamps@y..., Kevin Olalde <kolalde@h...> wrote:
> > > Can the 7812 be skipped? I'm not saying that's what the
original
> > problem is,
> > > just wondering why the whole curcuit can't just be run from the
same
> > 7805 (or is
> > > there a specific need for 12V)?
> > >
> > > Kevin
> > >