On Thu, 20 Oct 2005 15:25:39 +0100, KD7QAE wrote:
>almost all modern computer power supplies are now switch mode types and
>draw pure sine wave current in phase with the voltage. This is due to the
>use of active power factor correction which was mandated in world trade
>power supplies
There may be some supplies of the type you describe, but the vast majority
are of the type I described. I think that if you hang a current clamp and a
scope on most circuits you will see harmonics, and if you look inside, you
will see a capacitor-input filter. You will also see the harmonics if you
hang a scope on the power wiring.
The mandate you are speaking of is a European standard, and has no force in
most other parts of the world.
Jim
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