Jonathan de Boyne Pollard wrote in a message to Will Honea:
 WH> A switcher works by doing a power conversion - the power drawn from
 WH> the input supply and the power drawn from it's output are (ideally)
 WH> equal.
 JdBP> I'll admit to having never seen a circuit diagram for a
 JdBP> voltage regulator.  So I wouldn't mind some more information
 JdBP> on exactly how this works. 
A linear regulator deals with the difference between its input and output by 
simply "eating" it,  dissipating it as heat.  So,  for example,  if you have 
a five volt output needed at say six amps,  and the input to the regulator is 
say eight volts,  then (8-5)*6  or 18 watts of power needs to be dissipated 
as heat.
A switcher involves some sort of an oscillator circuit,  which periodically 
(at a fairly high rate) dumps some charge into storage capacitors at the 
output side of the circuit.  Variations in load and so forth are dealt with 
by feedback controlling either the frequency of the oscillator or the width 
of the pulses,  but since the switching devices are either hard on (very low 
resistance) or completely off,  their power dissipation is minimized.
That help any?  (I'm an electronics tech and am never sure when trying to 
explain stuff to non-tech people... :-)  I also have a couple of FAQ files 
around that get into much more details on this stuff,  if you're interested.
email: roy.j.tellason%tanstaaf@frackit.com 
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