[sdiy] Changing 15v power to 12v?

[Tom Arnold]

On Sat, Apr 18, 2015 at 01:02:41AM -0500, mskala at ansuz.sooke.bc.ca wrote:
> On Fri, 17 Apr 2015, Tom Arnold wrote:
> > the voltage.  I had one, but sold it.  You could email Blacet and check but I
> > think its a fairly common LM723 regulator circuit.  On the common PowerOne
> > supplies which are also LM723 based, for 12v operation you lift or change a
> > couple resistors.  They even print the instructions on the case.
> 
> Adjusting a linear regulator like this to a lower output voltage without
> changing the input voltage will increase the voltage drop across the
> regulator and therefore (for the same output current) its power
> dissipation and the amount of cooling it needs.

Yupp.  The PowerOne's typically have the amount to derate by also printed on
the case.  Still more efficient to adjust the power supply vs adding another
layer of regulation, unless you go with one of the bucking regulators and then
you can run into noise issues. 

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