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** Small variations in the 12V and some other rail voltages are quiteHello, I have an ATX power supply. I tested it with a CD ROM drive
attached and noticed that the 12V rail gives me a lower voltage when
the CD tray is moving (11.79V against the usual 11.87V).
Could this be due to bad capacitors?
the others are determined by transformer ratio, and are moreHello, I have an ATX power supply. I tested it with a CD ROM drive
attached and noticed that the 12V rail gives me a lower voltage when
the CD tray is moving (11.79V against the usual 11.87V).
Could this be due to bad capacitors?
Often only one of the voltages, for example the the 5volt, is regulated,
Right. All ATX power supplies are identical. Maker and model please?Hello, I have an ATX power supply.
If you're getting 10mv accuracy with your DVM, you must have a decentI tested it with a CD ROM drive
attached and noticed that the 12V rail gives me a lower voltage when
the CD tray is moving (11.79V against the usual 11.87V).
Could this be due to bad capacitors?
Maker: WhatsupRight. All ATX power supplies are identical. Maker and model please?
Some power supplies are junk.
Perhaps mine is in that league!
** How pedantic and idiotic !!!I tested it with a CD ROM drive
attached and noticed that the 12V rail gives me a lower voltage when
the CD tray is moving (11.79V against the usual 11.87V).
Could this be due to bad capacitors?
If you're getting 10mv accuracy with your DVM, you must have a decent
way of calibrating your instrument to that resolution. 100mv accuracy
is more reasonable.
Sorry. I've never heard of that brand. The part number is ratherJeff Liebermann <jeffl@cruzio.com> wrote:
Right. All ATX power supplies are identical. Maker and model please?
Maker: Whatsup
Model: ATX-400W P4
The drop is fairly normal for a power supply going from no load toMy concern is not how off the voltage is, it's the instability: is it
normal? The voltage changes depending on the load. The PSU inside my
PC doesnt do this.
I've never heard of a Whatsup power supply. Neither has Google. ThatSome power supplies are junk.
Perhaps mine is in that league!
Wellll ..."Jeff Liebermann"
[O.P. wrote:]
I tested it with a CD ROM drive attached and noticed that the 12V
rail gives me a lower voltage when the CD tray is moving (11.79V
against the usual 11.87V). Could this be due to bad capacitors?
If you're getting 10mv accuracy with your DVM, you must have a
decent way of calibrating your instrument to that resolution. 100mv
accuracy is more reasonable.
** How pedantic and idiotic !!!
The OP is only asking about the small DROP in voltage he measured under
load - which NOT dependant on calibration or accuracy of the meter.
The LINEARITY of most DMMs is of a very high order - 1 part in 1000 is
typical.
Pedantic"Jeff Liebermann"
I tested it with a CD ROM drive
attached and noticed that the 12V rail gives me a lower voltage when
the CD tray is moving (11.79V against the usual 11.87V).
Could this be due to bad capacitors?
If you're getting 10mv accuracy with your DVM, you must have a decent
way of calibrating your instrument to that resolution. 100mv accuracy
is more reasonable.
** How pedantic and idiotic !!!
The accuracy of the DVM's ability to measure 12.000000000 VDC isThe OP is only asking about the small DROP in voltage he measured under
load - which NOT dependant on calibration or accuracy of the meter.
Linearity is usually +/- 1 bit or LSB. If it's a 3 1/2 digit cheapoThe LINEARITY of most DMMs is of a very high order - 1 part in 1000 is
typical.
"Jeff Liebermann"
[O.P. wrote:]
I tested it with a CD ROM drive attached and noticed that the 12V
rail gives me a lower voltage when the CD tray is moving (11.79V
against the usual 11.87V). Could this be due to bad capacitors?
If you're getting 10mv accuracy with your DVM, you must have a
decent way of calibrating your instrument to that resolution. 100mv
accuracy is more reasonable.
** How pedantic and idiotic !!!
The OP is only asking about the small DROP in voltage he measured under
load - which NOT dependant on calibration or accuracy of the meter.
The LINEARITY of most DMMs is of a very high order - 1 part in 1000
is typical.
Wellll ...
Isn't the correct answer here "don't worry about it"?
If you're getting 10mv accuracy with your DVM, you must have a decent
way of calibrating your instrument to that resolution. 100mv accuracy
is more reasonable.
** How pedantic and idiotic !!!
Pedantic
-adjective
1. ostentatious in one's learning.
2. overly concerned with minute details or formalisms, esp. in
teaching.
Ummmm... ok.
The OP is only asking about the small DROP in voltage he measured under
load - which NOT dependant on calibration or accuracy of the meter.
** More pedantic BOLLOCKS.The question was whether the power
supply was defective, which in my opinion is more a matter of keeping
the output voltage within the specifications (with any load).
** ROTFLMAO !!!!!The LINEARITY of most DMMs is of a very high order - 1 part in 1000 is
typical.
Linearity is usually +/- 1 bit or LSB. If it's a 3 1/2 digit cheapo
DVM, with a full scale reading of 1999, it probably has 10 bit A/D
converter.
** Crapology.1 bit error = 20.0 V / 2000 = +/- 10 mv error.
For an 80 mv difference, there's a 40 mv uncertainty due to
non-linearity (+/-10 mv error for the no-load, and another +/-10 mv
for the loaded readings).
Thanks. I didn't know that. The DVM's I play with all have SARThe LINEARITY of most DMMs is of a very high order - 1 part in 1000 is
typical.
Linearity is usually +/- 1 bit or LSB. If it's a 3 1/2 digit cheapo
DVM, with a full scale reading of 1999, it probably has 10 bit A/D
converter.
Regular DMMS do not use conventional A-D converters.
They use "dual slope integration " - ie an analogue technique.
The "digital" bit is the fucking display.
That's also the linearity if everything else were perfect. ReadingThe same meter is used and so the only error is the +/-1 bit display
uncertainty.
OK, so my guess is, oh, another week or so before Phil posts a calm,"Jeff Liebermann = a lying AUTISTIC ASSHOLE "
** Drop dead you pathetic fuckwit.
"Jeff Liebermann = a lying AUTISTIC ASSHOLE "
** Drop dead you pathetic fuckwit.
OK, so my guess is, oh, another week or so before Phil posts a calm,
reasonable (and correct) message here.
Agree- somewhat."David Nebenzahl is Donkey Brained Troll "
"Jeff Liebermann = a lying AUTISTIC ASSHOLE "
** Drop dead you pathetic fuckwit.
OK, so my guess is, oh, another week or so before Phil posts a calm,
reasonable (and correct) message here.
** Shame is pal, EVERY SINGLE TIME I do just that - a bunch of
fucking, autistic RETARDS like YOU come along afterwards and try to piss
on it.
Comes with the territory PhilSame all over damn usenet -
Including you.nothing but FUCKING TROLLS !!!!!!!!!!!
Sheesh. I agreed with part of what you said. I thanked you for the"Jeff Liebermann = a lying AUTISTIC ASSHOLE "
I appreciate your concern for my well being, but I think I can** Drop dead you pathetic fuckwit.
So you see, Jeff, it's basically a medical problem, not an etiquette issue."Jeff Liebermann = a lying AUTISTIC ASSHOLE "
** Drop dead you pathetic FUCKWIT !!!