Re: How much Voltage Drop is acceptable for computers? Outdoor Desktop

From: Paul Burridge (pb_at_notthisbit.osiris1.co.uk)
Date: 08/29/04 

Date: Sun, 29 Aug 2004 12:57:49 +0100

On 29 Aug 2004 03:57:22 -0700, Winfield Hill
<Winfield_member@newsguy.com> wrote:

>Robert Baer wrote...
>>
>> Say you used 12 AWG, that would be about 0.8 ohms; at 2 amps
>> current (crudely 250 watts) that would give a drop about 1.6 volts
>> - which is not enough to worry about.
>
> BUT, most computer and monitor power supplies are not PFC, not
> power-factor corrected, and draw their current in a short pulse
> in the middle of the sine wave. With a stiff source impedance
> they draw about 10x the rms current, so that'd be 20A and a 16V
> drop. Of course we'd not call 0.8 ohms a stiff source, so the
> pulse wold be spread out some and the drop a bit less severe.

"Stiff source impedance"? I know what you mean, but have never
encountered that curious term before... 

-- 
"What is now proved was once only imagin'd." - William Blake, 1793.

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