What PSU rating for Athlon 2400 with 6 HDDs?

[CBFalconer]

I didn't believe it until I visited their website. This has got
to be the first time that a company has admitted that its most
prominently advertised power rating was for peak power. Is it a
sign of greater honesty, or of lower standards?

Are you sure that Q-tec is a step above no-names? This picture of the
insides of their 550W model: www.bit-tech.net/images/review/123/7.jpg
Makes i seem more like a decent 250W.

5 Va.c. _________\|____ 1 k ohm ___________________ 5 V out
/| | |
diode | |
1000 uF 5V zener
|________|
|
gnd

should provide 5v regulated with a 600 or more peak power output
rating. Depends only on the quality of the capacitor. Maybe I
should go into business.

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

5 Va.c. _________\|____ 1 k ohm ___________________ 5 V out
/| | |
diode | |
1000 uF 5V zener
|________|
|
gnd

should provide 5v regulated with a 600 or more peak power output
rating. Depends only on the quality of the capacitor. Maybe I
should go into business.

600 or more _what_?

Where do you get 5VAC?

 

[JW]

600 or more _what_?

I'm assuming he meant watts, but...

Where do you get 5VAC?

More importantly, if he did mean watts, I'd like to see how it'll get
through that 1k resistor

 

[David Maynard]

I'm assuming he meant watts,

"Peak" watts.

but...




More importantly, if he did mean watts, I'd like to see how it'll get
through that 1k resistor

Easy. It charges the capacitor back up, over time.

 

[Tom MacIntyre]

"Qtec" - for example - are a very popular low-end

It means that they must have been manufacturers of computer speakers
before they started with power supplies?

Tom

 

[kony]

It means that they must have been manufacturers of computer speakers
before they started with power supplies?

Tom

LOL, that's exactly what i was thinking.

 

[CBFalconer]

I'm assuming he meant watts, but...


More importantly, if he did mean watts, I'd like to see how
it'll get through that 1k resistor

It doesn't have to. I said peak, which is supplied by the
capacitor alone. The point is that the (flawed) specification can
be filled with about two bits worth of parts. The requirement, for
500 W. peak at 5V, is that the capacitor can supply 100 A. for any
period, no matter how minute. You can use as small a capacitor as
you like, also, provided it has low internal resistance.

 

[Michael Brown]

Watson A.Name wrote :

I'm assuming he meant watts, but...


More importantly, if he did mean watts, I'd like to see how it'll get
through that 1k resistor

Err, I think he was making a joke The above circuit would indeed supply
600W of power at something around 5V for a very brief period of time if the
capacitor was up to it. Assuming we're talking ATX tolerances (5% on 5V
IIRC), the supply voltage would be allowed to drop to 4.75V before it became
out of spec. If the "power supply" was allowed to be on for a while before
any load was applied (ie: it charges up the capacitor) then a 1000uF
capacitor should be able to hold it within spec at a 600W load for about
2uS. The resistor and power source don't have a big impact while the load is
applied precicely for the reason you noted: the resistor limits to
satisfying a ~6mW load at best.

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

"Peak" watts.


Easy. It charges the capacitor back up, over time.

There is no time factor in watts.

 

[David Maynard]

There is no time factor in watts.

But there is in charging a capacitor through a fixed resistor.

 

[Franklin]

"Qtec" - for example - are a very popular low-end

I didn't believe it until I visited their website. This has got
to be the first time that a company has admitted that its most
prominently advertised power rating was for peak power.

Does anyone have any 'real' specs for this PSU? You know what I
mean, the normal sort of data in a chart.

I can't find any at their website. I am overlooking a small but
significant link?

http://www.qtec.info/products/group.htm?pc=POWER-SUPPLY-UNITS

 

[Watson A.Name - \Watt Sun, the Dark Remover\]

But there is in charging a capacitor through a fixed resistor.

As a matter of fact, you can't store a single watt in that capacitor.
You might store so many coulombs of charge at a certain voltage, but not
watts.

Wattage is dissipation, and if you put a low resistane across the
charged capacitor to get a lot of current, there would be little
dissipation, even for a short time. To get 600W or 120A at 5VDC, the
resistor would be about .04 ohms, and that is probably not much more
than the ESR of the capacitor.

 

[Franklin]

Absolutely correct. "Qtec" - for example - are a very popular
low-end brand. You might refer to them as a no-name, but
arguably they are one step up from that. They produce a very
popular 550w PSU.

Poor old Qtechnology - who make some half-decent PSUs. They must be
sick of having a name so silimar to that of Q-Tec.

http://www.qtec.info/products/
http://www.qtechnology.net/products.htm

And don't forget to throw in a hyphen into Q-Tec but not into
QTechnology. Omit the hyphen from both their URLs. The potential
for confusion keeps on growing!

 

[Franklin]

Any/all of these can vary current. One board may default
memory to different voltage, another may be running at
higher FSB speed, then the obvious things like chipset or
processor count too... these differences could offset each
other or add up to a signficant difference in some cases.
Even so, the difference between one motherboard and another
will often be much less than the difference between one CPU
or another (if large enough frequency or voltage, core
change), or comparing a budget video card to a high-end
model, or number of hard drives.

Which compenents in a PC tend to use the +3.3V supply? Is it
*typically* the cpu, mobo and memory?

 

[David Maynard]

Does anyone have any 'real' specs for this PSU? You know what I
mean, the normal sort of data in a chart.

I can't find any at their website. I am overlooking a small but
significant link?

I never found anything 'real' on their site either. The only thing I came
up with earlier (but don't have handy) was a customer 'review' on a site
selling them and he claimed to have received an email from them, and posted
the data. The best recollection I have is that the 'real' numbers were 20
to 40% less, depending on the power rail, than the amps put on the sticker.

 

[David Maynard]

As a matter of fact, you can't store a single watt in that capacitor.
You might store so many coulombs of charge at a certain voltage, but not
watts.

I didn't say anything about 'storing watts'. The operative word was "time."
As in "there is no time factor in" ... "but there is in."

Wattage is dissipation, and if you put a low resistane across the
charged capacitor to get a lot of current, there would be little
dissipation, even for a short time.

Correct. A real SHORT period of time. But for that short period of time you
could hit '600 watts', under the right conditions.

Then a lot longer to charge the cap back up before you could get another
jolt of "600 peak watts." But, by golly, you can get "600 peak watts" out
of it.

To get 600W or 120A at 5VDC, the
resistor would be about .04 ohms, and that is probably not much more
than the ESR of the capacitor.

You've missed the whole point of his demonstration diagram. The context was
Qtec rating their PSU with "peak watts" and he's showing, with an absurd
circuit, that a "peak power" rating means absolutely nothing except,
perhaps, that it has a low impedance output.

 

[kony]

Which compenents in a PC tend to use the +3.3V supply? Is it
*typically* the cpu, mobo and memory?

Not CPU. Motherboard may, memory might, but those too can
use 5V, depends on particular manufacturer's design.

 

[Chip]

As a matter of fact, you can't store a single watt in that capacitor.
You might store so many coulombs of charge at a certain voltage, but not
watts.

Wattage is dissipation, and if you put a low resistane across the
charged capacitor to get a lot of current, there would be little
dissipation, even for a short time. To get 600W or 120A at 5VDC, the
resistor would be about .04 ohms, and that is probably not much more
than the ESR of the capacitor.

Ever seen an electronic flash on a camera?

Hint: the flash is *very* short in duration.

Chip

 

[Chip]

I never found anything 'real' on their site either. The only thing I came
up with earlier (but don't have handy) was a customer 'review' on a site
selling them and he claimed to have received an email from them, and
posted the data. The best recollection I have is that the 'real' numbers
were 20 to 40% less, depending on the power rail, than the amps put on the
sticker.

I found this:

http://www.bit-tech.net/images/review/123/5.jpg

 

[David Maynard]

I found this:

http://www.bit-tech.net/images/review/123/5.jpg

Ah. So they put both on the label. ok.