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

[David Woolley]

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.

-- 
David Woolley K2 06123

On 25/04/17 04:51, Jim Brown wrote:
> The reason for using 240VAC is to reduce the IR drop in the AC line,
> which, BTW, is not sinusoidal, but rather pulses that charge the filter
> caps at the peaks of each cycle. So the drop in the wire is even greater
> than Ohm's law appliced to a sine wave would predict.