Power consumption of a typical computer

[Jacky]

I reckon today's computers use constant voltage and current...
So the power consumption is constant.
But why today's mobos use 3-phase (or more) power supply to stabilize the
current...
Are there anything wrong with the above statements?
Thanks
Jack

 

[Bob Masta]

On Tue, 4 Dec 2007 16:53:33 +0800, "Jacky" <jl@knight.com> wrote:

I reckon today's computers use constant voltage and current...
So the power consumption is constant.

No way! Modern computers have quite elaborate power management
systems. The CPU itself has a wide range of power levels depending on
the moment-to-momenf computation demands, plus the rest of the
computer has things like hard drives, DVD, etc, whose demands change.

But why today's mobos use 3-phase (or more) power supply to stabilize the
current...
Are there anything wrong with the above statements?
Thanks
Jack

They use switchmode supplies that maintain the *voltage* in the face
or changing current needs.

Best regards,


Bob Masta

DAQARTA v3.50
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, FREE Signal Generator
Science with your sound card!

 

[default]

On Tue, 4 Dec 2007 16:53:33 +0800, "Jacky" <jl@knight.com> wrote:

I reckon today's computers use constant voltage and current...
So the power consumption is constant.

Today's computers use switching supplies with power factor correction
- but they still use power based on what they are doing, shutting down
a drive or accessing a drive uses less or more power - although its
not likely to be enough of a difference to spot with a meter.

The processor power itself can vary widely between different runs of
chips (stampings) but most folks don't change processors just replace
the whole computer when it gets old. "Overclocking" raising the speed
of a processor by switching jumpers on a motherboard - will result in
higher power consumption and heat loading, the converse is also true.

But why today's mobos use 3-phase (or more) power supply to stabilize the
current...
They use single phase power from the wall plug and have several DC

outputs to service various components and protocols 3.3V, 5 V, -5V,
+12V, -12V - and there are likely to be additional regulators on the
mother board for other functions.

3 phase or more? Don't know where you came up with that one. single
phase AC from the outlet and DC (no phases) to the parts.

3 phase doesn't stabilize anything.

The fans and motors can be said to use multiphase power, but they
generate it internally from DC power supplies.

Are there anything wrong with the above statements?

Yes. Practically all of the statements.


There's lots of good reasons to lower power consumption.
Lower operating cost.
Fewer cooling requirements.
Smaller size.
Lower cost of materials - even if the higher cost of technology to
make it smaller offsets that a bit.

--
---- Posted via Pronews.com - Premium Corporate Usenet News Provider ----
http://www.pronews.com offers corporate packages that have access to 100,000+ newsgroups

 

[default]

On Tue, 4 Dec 2007 16:53:33 +0800, "Jacky" <jl@knight.com> wrote:

I reckon today's computers use constant voltage and current...
So the power consumption is constant.

They try to hold the Voltage constant the current varies with demand.
Power (Watts) = Voltage (Volts) X Current (Amps)

A very wide slowly moving river may represent an enormous amount of
Power even if the pressure is very low - while a garden hose with a
high pressure stream of water may represent a very small amount of
power.

Voltage = pressure
Current = rate of flow
--
---- Posted via Pronews.com - Premium Corporate Usenet News Provider ----
http://www.pronews.com offers corporate packages that have access to 100,000+ newsgroups

 

[default]

On Wed, 5 Dec 2007 17:37:37 -0800 (PST), w_tom <w_tom1@usa.net> wrote:

Computers don't use 3-phase. Home traditionally use two phase
electricity. Computers are powered only from one of those two phases.
Power supply output has no phases because it is not AC; it is DC.
What exactly is your question?

Single phase center tapped 240 volt transformer - in the US.
--
---- Posted via Pronews.com - Premium Corporate Usenet News Provider ----
http://www.pronews.com offers corporate packages that have access to 100,000+ newsgroups