On Fri, 12 Sep 2008, the dip**** wrote:
>
> Hello, I am wondering if anyone knows the pin layout for a l7812acv
cc077 v6
> march 819 and a l7912acv gk243 vw chn 734. The products where purchased
via
> newark.com from ST electronics. I checked the datasheets and the three
that
> I have read all provide different pin layouts. I like to be sure that I
get
> the pins right before I start pulling from the transformer - it's just a
> minor issue but the koreans TL431 datasheet is much different than the
ones
> that are available to US citizens.
>
The 7812 is a positive regulator, the 7912 is a negative voltage
regulator, and the two never had the same pinout.
If you're looking at both and thinking they are different, that's because
they are.
Assuming they are TO-220 packages (and if not, you should be specifying
it since all the peripheral junk around the basic part number is not
consistent from company to company and may not tell us anything):
7812 7912
----- -----
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I G O G I O
I=input
G=ground
O=output
In both cases, the tab connects to the center pin, which means it's ground
on the 7812 and input on the 7912.
This is the standard method of showing the pins, you will be looking at
the regulators and seeing the part number on the plastic; the tab is
further away from you.
Michael
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