[mythtv-users] Desk Top Power

[Karl Newman]

On Sat, May 16, 2015 at 10:54 AM, Stephen P. Villano <
stephen.p.villano at gmail.com> wrote:

>
>
> On 5/16/15 12:59 PM, Simon Hobson wrote:
> > Michael Watson <michael at thewatsonfamily.id.au> wrote:
> > jrh <jharbestonus at gmail.com> wrote:
> >
> >> Regarding power imbalance or however it is called, is this still an
> issue for power supplies built today?
> > Yes I would say for a typical PC PSU.
> > The multiple outputs typically come from multiple secondary windings and
> rectifiers from one transformer. The feedback control operates on the
> primary output - it's only possible to accurately regulate one output
> without secondary regulators. The other rails will more or less follow the
> main one - the relationship between output voltages depends on the ratio of
> the number of turns on the transformer, and the voltage drop in the
> rectifier diodes and windings.
> > If you keep the load on the primary output constant, then varying the
> load on one of the secondary outputs will vary the voltage on that output -
> increase load and the voltage will droop, reduce it and the voltage will
> rise.
> >
>  Tesla and Edison had a longstanding argument, Tesla advocated for
> alternating current, Edison advocated for direct current. As alternating
> current has less losses in long transmission lines than direct current,
> Tesla's argument won by means of feasibility.
>

To be pedantic, at equivalent voltage & particularly current levels, I
think AC is actually more lossy than DC due to skin effect, hysteresis and
eddy currents (although the last 2 probably mostly apply to transformers).
Tesla "won" because it's much easier/efficient to change AC to high
voltage suitable for transmission and then back down again for distribution
using transformers.

Karl
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