[sdiy] most efficient way to get 5V from 12V?

[David G. Dixon]

What I've done is simply put a 78L05 (TO-92 package) on the board.  It will
source up to 100mA.  If you are using reasonably low-power digital chips
(CMOS, not TTL) then this should be OK.  My keyboard matrix scanner PCBs are
nearly all digital, and one 78L05 powers the lot without getting the
slightest bit warm.  I put one 10uF bypass cap on the 5V line for digital
noise suppression.

This technique gives you the power where you need it, and saves you having
to retrofit a +5V supply into your whole system.


> If I want to run the digital parts of my module at 5V I am going to
> need to convert the 12V source. On some Euro modules the 5V conversion
> is done externally via a Doepfer 5V adapter (just has a regulator and
> a heatsink on it and plugs into the bussboard)
> 
> Is there any reason that I can't do this on the module?  If I do it
> there, what is the most efficient way (i.e. generates the least heat)
> so that I don't need a large heat sink?
> 
> cheers,
> Danjel
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