[Elecraft] Another really good reason to come to the Visailia DX convention this weekend...

[Alan Bloom]

The IEC 555 standard (later superseded by IEC 61000-3-2) specifies 
allowed harmonic distortion in the power supply current of electronic 
equipment:

https://en.wikipedia.org/wiki/IEC_61000-3-2

I believe it is mandatory in Europe and some other countries but not the 
United States:

http://www.metlabs.com/emc/emc-testing-requirement-for-it-equipment-varies-by-country/

Alan N1AL


On 04/26/2017 04:04 AM, David Woolley wrote:
> I don't believe that it is legal to market a power supply that only
> draws current on input peaks in either the USA or EU these days.  Power
> supplies are supposed to spread the current demand over a significant
> part of the cycle.  I believe this is done by having a relatively low
> value capacitor on the mains side and relying on the switching regulator
> to compensate for the wide voltage variations across each cycle.  I
> believe that even applies to wall warts.
>
> This "power factor correction" will not be perfect, so the peak current
> will still be more than for a resistive load.
>