U
Unknown
Where have you seen it hundreds of times? Give facts not emotions.
T
Tim Slattery
Unknown said:
A power supply in any electronic gizmo changes 110V (usually) AC to
one or more voltages of DC, generally something like 5V - 20V, I
think.
Anyway, the voltage changing is done by a transformer. The
lower-voltage AC from the secondary coil of the transformer is then
fed to one (or sometimes more) rectifiers. That's a circuit component
that allows current to flow in only one direction. Now you have DC,
but very lumpy DC: it oscillates between no current at all and the
required voltage. Not much equipment can use the juice in that state.
So it needs to be "smoothed" (that is the term that's used). That is
accomplished by putting a capacitor - usually a pretty large
electrolytic capacitor - across the line. The capacitor stores charge
when the voltage goes up and releases it as the voltage drops, thereby
smoothing out the peaks and valleys.
A
Androcles
Even more amusing is dynamic RAM that uses the charge on
a capacitor to store bits.
http://en.wikipedia.org/wiki/Dynamic_random_access_memory
: No he's not. Capacitors do NOT smooth current. They reduce or eliminate
: voltage fluctuations.
: : >>
: >> in message
: >>
: >> :: >> : >
: >> : > Capacitors.
: >> : >
: >> :
: >> :
: >> : capacitors usually discharge when the current is switched off - their
: >> main
: >> : job is to smooth current, not to store volts....
: >>
: >> That shows how much you know -- which is zilch.
: >
: > He's right. In a computer that's what they're for. Sure they can still
: > store charge without any current flowing, but that's not their
: > intended purpose. Many of them will automatically discharge straight
: > away into the heavy loads they're connected to. But in the power
: > supply are capacitors which do retain their charge after switching
: > off.
: >
: > Not sure what this has to do with stopping the computer from working,
: > clearly there's an actual problem that should be fixed to prevent it
: > happening again.
: >
: >
:
:
a capacitor to store bits.
http://en.wikipedia.org/wiki/Dynamic_random_access_memory
: No he's not. Capacitors do NOT smooth current. They reduce or eliminate
: voltage fluctuations.
: : >>
: >> in message
: >>
: >> :: >> : >
: >> : > Capacitors.
: >> : >
: >> :
: >> :
: >> : capacitors usually discharge when the current is switched off - their
: >> main
: >> : job is to smooth current, not to store volts....
: >>
: >> That shows how much you know -- which is zilch.
: >
: > He's right. In a computer that's what they're for. Sure they can still
: > store charge without any current flowing, but that's not their
: > intended purpose. Many of them will automatically discharge straight
: > away into the heavy loads they're connected to. But in the power
: > supply are capacitors which do retain their charge after switching
: > off.
: >
: > Not sure what this has to do with stopping the computer from working,
: > clearly there's an actual problem that should be fixed to prevent it
: > happening again.
: >
: >
:
:
A
Androcles
:
: >No he's not. Capacitors do NOT smooth current. They reduce or eliminate
: >voltage fluctuations.
:
: A power supply in any electronic gizmo changes 110V (usually) AC to
: one or more voltages of DC, generally something like 5V - 20V, I
: think.
:
: Anyway, the voltage changing is done by a [snip transformer]
switching regulator.
http://www.national.com/appinfo/power/files/f5.pdf
: >No he's not. Capacitors do NOT smooth current. They reduce or eliminate
: >voltage fluctuations.
:
: A power supply in any electronic gizmo changes 110V (usually) AC to
: one or more voltages of DC, generally something like 5V - 20V, I
: think.
:
: Anyway, the voltage changing is done by a [snip transformer]
switching regulator.
http://www.national.com/appinfo/power/files/f5.pdf
B
Bob I
Androcles said:
Humm, pretty much ALL of our current energy use comes originally from
"nuclear fusion".
A
Androcles
:
:
: Androcles wrote:
:
: > : >
: >>Gordon wrote:
: >>
: >>>: >>>
: >>>>Capacitors.
: >>
: >>>capacitors usually discharge when the current is switched off - their
: >>>main
: >>>job is to smooth current, not to store volts....
: >>
: >>True, but they don't discharge instantaneously. Ever hear about the
: >>"time constant" of an R-C circuit?
: >>
: >>T = R × C
: >>where:
: >>T = time constant in seconds
: >>R = resistance in ohms
: >>C = capacitance in farads
: >>
: >>The time constant is the time taken for the charging (or discharging)
: >>current (I) to fall to 1/e of its initial value (Io).
: >>
: >>After each time constant the current falls by 1/e (about 1/3). After 5
: >>time constants (5RC) the current has fallen to less than 1% of its
: >>initial value and we can reasonably say that the capacitor is fully
: >>(dis)charged, but in fact the capacitor takes for ever to (dis)charge
: >>fully!
: >>
: >>--
: >>Lem -- MS-MVP - Networking
: >>
: >>To the moon and back with 4KB of RAM and 72KB of
:: >
: >
: > Yes,To the moon and back with 4KB of RAM and 72KB of ROM.
: > So why can't some one harness nuclear fusion for our energy needs?
: >
: > 1) Don't need to, your energy needs are really your energy wants.
: > Mankind can survive without the inefficient use of energy and has
: > done for millions of years, as do all other species on this planet.
: > There is a huge difference between need and want.
: >
: > 2) The equations are wrong, the fools are fiddling with Einstein's
: > relativity and it doesn't work.
: >
: > So why can't *you* harness nuclear fusion for *my* energy wants?
: >
:
: Humm, pretty much ALL of our current energy use comes originally from
: "nuclear fusion".
Yep
:
: Androcles wrote:
:
: > : >
: >>Gordon wrote:
: >>
: >>>: >>>
: >>>>Capacitors.
: >>
: >>>capacitors usually discharge when the current is switched off - their
: >>>main
: >>>job is to smooth current, not to store volts....
: >>
: >>True, but they don't discharge instantaneously. Ever hear about the
: >>"time constant" of an R-C circuit?
: >>
: >>T = R × C
: >>where:
: >>T = time constant in seconds
: >>R = resistance in ohms
: >>C = capacitance in farads
: >>
: >>The time constant is the time taken for the charging (or discharging)
: >>current (I) to fall to 1/e of its initial value (Io).
: >>
: >>After each time constant the current falls by 1/e (about 1/3). After 5
: >>time constants (5RC) the current has fallen to less than 1% of its
: >>initial value and we can reasonably say that the capacitor is fully
: >>(dis)charged, but in fact the capacitor takes for ever to (dis)charge
: >>fully!
: >>
: >>--
: >>Lem -- MS-MVP - Networking
: >>
: >>To the moon and back with 4KB of RAM and 72KB of
:: >
: >
: > Yes,To the moon and back with 4KB of RAM and 72KB of ROM.
: > So why can't some one harness nuclear fusion for our energy needs?
: >
: > 1) Don't need to, your energy needs are really your energy wants.
: > Mankind can survive without the inefficient use of energy and has
: > done for millions of years, as do all other species on this planet.
: > There is a huge difference between need and want.
: >
: > 2) The equations are wrong, the fools are fiddling with Einstein's
: > relativity and it doesn't work.
: >
: > So why can't *you* harness nuclear fusion for *my* energy wants?
: >
:
: Humm, pretty much ALL of our current energy use comes originally from
: "nuclear fusion".
Yep
?
=?windows-1252?Q?JDa=99=A9?=
There is a easier way. Power down, unplug the power cord, then press
and hold down the ON button for a count of 8, then reconnect the power
cord, and power up again.
Pressing the On button assures that the capacitors are fully discharged.
Unknown, did transcribed the following::
and hold down the ON button for a count of 8, then reconnect the power
cord, and power up again.
Pressing the On button assures that the capacitors are fully discharged.
Unknown, did transcribed the following::
H
HeyBub
Unknown said:
Is too!
U
Unknown
Power supply is fine!
HeyBub said:
L
Leythos
I've been working with/on computers for almost 30 years, PM has been a
problem for at least 10 of those years.
I'm stating facts, I don't state emotions.
--
Leythos
- Igitur qui desiderat pacem, praeparet bellum.
- Calling an illegal alien an "undocumented worker" is like calling a
drug dealer an "unlicensed pharmacist"
(e-mail address removed) (remove 999 for proper email address)
U
Unknown
Spoof!
Leythos said:
S
Stuart
In computers - yes, the PSU is always switch mode but that is not the case
with all equipment.
Particularly in sensitive equipment, where switchers would generate too
much crap and interfere with equipment operation linears are still used.
--
Stuart Winsor
From is valid but subject to change without notice if it gets spammed.
For Barn dances and folk evenings in the Coventry and Warwickshire area
See: http://www.barndance.org.uk
S
srp
I suppose you have some model of Dell flat screen with this computer ?
If so, it may not be the computer at fault but the monitor.
I ran into similar problem and also thought that the computer was
bugged. Actually, the computer booted fine, but the monitor
was at fault.
If you haven't resolved it yet, here is how it was resolved for me.
There was need to completely disconnect the flat screen
power cord from the wall socket (easier there than at the
flat screen end) and wait a while.
The flat screen micro then rebooted correctly upon reconnection
and repowering.
My interpretation was that there is some builtin flash memory
chip into the monitor circuit that keeps some settings that
had become corrupt. The control pin of that chip no
doubt remains powered even if you turn the monitor off
without completely disconnecting the power cord.
André MIchaud
L
Leythos
Is there a reason that you've taken to spouting crap instead of being
able to disprove real world experience?
PM has long been problematic on cheap/badly designed motherboards -
prove me wrong instead of being a child/troll.
--
Leythos
- Igitur qui desiderat pacem, praeparet bellum.
- Calling an illegal alien an "undocumented worker" is like calling a
drug dealer an "unlicensed pharmacist"
(e-mail address removed) (remove 999 for proper email address)
U
Unknown
You're the one that made the ridiculous statement. Then you say that's your
experience.
My experience is opposite.
experience.
My experience is opposite.
L
Leythos
And your experience doesn't invalidate what I've said.
My experience does invalidate your experience as being the definitive
answer. While you may not have the experience for what ever reason, I do
and I've seen it happen on cheap/crappy motherboards and even good ones
that had bad firmware, hundreds of times.
You might learn something from those of us that have been around for a
while if you could take your head out of your a$$.
--
Leythos
- Igitur qui desiderat pacem, praeparet bellum.
- Calling an illegal alien an "undocumented worker" is like calling a
drug dealer an "unlicensed pharmacist"
(e-mail address removed) (remove 999 for proper email address)
U
Unknown
More emotional nonsense. What was the name of the manufacturer of the
boards? What computer manufacturer?
You seen hundreds! What problem did they cause? What was the design
deficiency? What was the technology that failed?
Hundreds of times????? Give us the data.
boards? What computer manufacturer?
You seen hundreds! What problem did they cause? What was the design
deficiency? What was the technology that failed?
Hundreds of times????? Give us the data.
A
Androcles
: In article <[email protected]>,
: > : Anyway, the voltage changing is done by a [snip transformer]
: > switching regulator.
: > http://www.national.com/appinfo/power/files/f5.pdf
:
: In computers - yes, the PSU is always switch mode but that is not the case
: with all equipment.
It's a computer we are talking about. We've had transformers
and bridge diodes since the dark ages but some people have
never evolved from their train set with its transformer, selenium
rectifier and rheostat.
http://www.theodoregray.com/PeriodicTable/Samples/034.10/s12s.JPG
http://img.alibaba.com/photo/51631125/Sliding_Rheostat_Specification.jpg
I was designing pulse width modulation controllers over 35 years ago,
the triac is older than that.
: > : Anyway, the voltage changing is done by a [snip transformer]
: > switching regulator.
: > http://www.national.com/appinfo/power/files/f5.pdf
:
: In computers - yes, the PSU is always switch mode but that is not the case
: with all equipment.
It's a computer we are talking about. We've had transformers
and bridge diodes since the dark ages but some people have
never evolved from their train set with its transformer, selenium
rectifier and rheostat.
http://www.theodoregray.com/PeriodicTable/Samples/034.10/s12s.JPG
http://img.alibaba.com/photo/51631125/Sliding_Rheostat_Specification.jpg
I was designing pulse width modulation controllers over 35 years ago,
the triac is older than that.
L
Leythos
I don't see any reason to be trolled by you.
--
Leythos
- Igitur qui desiderat pacem, praeparet bellum.
- Calling an illegal alien an "undocumented worker" is like calling a
drug dealer an "unlicensed pharmacist"
(e-mail address removed) (remove 999 for proper email address)
N
nottoooily
Oh yes they do don't they
In fact it's pretty much the opposite ofsmoothing current.
Well that's true of bypass capacitors that're used near chips. But I
think it's fair to say the input capacitors in a power supply do
smooth current by removing mains voltage fluctuations, and thereby
preventing current fluctuations in the downstream load. And in fact
those are the ones that can hold their charge after switching off.