AVR-Chat

--- In AVR-Chat@yahoogroups.com, Mike Perks <basicx@a...> wrote:
> Maximum is well above 13.6V. However the larger the difference, 
the more 
> heat needs to be disappiated by the regulator. You also mentioned 
that 
> you will need 1.5A which exceeds the specifications of the LM7805 
which 
> is limited to 1A. You will need something like a MC78T05 that is 
rated 
> at 3A.
> 
> I use 1N4001 or 1N4002 to protect both against polarity reversal 
and to 
> protect the regulator against reverse current flow (connect the 
cathode 
> to the regulator input). For your case you are going to need 
beefier 
> diodes such as 1N5402.
> 
> Regards,
> Mike

Thanks Mike.  I said that I need 1.5A mainly because I am using a 
1.5A reg right now and it only gets moderately warm, but not hot 
with the loads right now.  There would be a second LCD which is the 
major single load.  I believe that a 1A reg would work, but as I 
said, I'd rather over-build the supply section.

I will use some big diodes as protection.  Already I use a diode on 
the input to protect against reverse polarity 13.6V input.  This 
will drop the input voltage by a volt or so right there, taking some 
of the thermal load off the regulator, I suppose.

-Tony