[sdiy] speaking of power supplies...

[harrybissell]

Series cascaded regulators have the problem that the highest voltage regulator
must supply the total current used by all stages.  That could be a problem
if it uses a lot of current.  I will make a 5V supply from a 15V supply with
a cascaded regulator... but only for low current... and I'm willing to take the

inefficiency.

H^) harry

jhno wrote:

> > You are better off using a LM317 type *programmable* regulator.
>
> oh, i know - this is about the only one i use. however, one day i was out
> of 317, and had this pile of 7808's...
>
> i am still curious about the chained regulators because the concepts apply
> to multiple-voltage power supplies. typically a device might require +/- 12
> or 15 rail volts, and an additional +48v phantom, or +21v BBD power, etc...
>
> also i presume that, lacking a regulator designed for higher voltages, one
> could develop a +70v source from a pair of 317's.
>
> so i am just looking for caveats. mike irwin thought offhand that multiple
> regulators might react more slowly, as an example.
>
> thanks
> jhno