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jurb = jerkoff fool @gmail.com wrote:
With a bridge, only 2 diodes on 4 work
** No, they all work.
You got him on semantics, he probably meant "conduct". Sure they are working when they are conducting, but they are also working when not conducting. They are blocking. When they no longer block they are considered not working.
** All four diodes conduct - half of them during each half cycle.
With two diode, full wave rectifiers its one diode per half cycle.
The claim about extending diode life was bullshit
Just like every single claim YOU post.
..... Phil
With a bridge, only 2 diodes on 4 work
** No, they all work.
You got him on semantics, he probably meant "conduct". Sure they are working when they are conducting, but they are also working when not conducting. They are blocking. When they no longer block they are considered not working.
So it preserve diode life.
** False conclusion derived from a false assertion.
Also ignores some logic on the subject. I won't be as mean as you but I will say it - ijiot ! YOU pick the diodes, they don't pick you ! And do you care if the diode is 50 cents or 60 cents ?
I'm surprised I am even here. I did need a bit of a break though. Got any idea why the hell this Carver Receiver (MX-130) turns off the tuner when I turn off the speakers ? I decided to get away from it, and now I think I have a clue, it switches by relay, maybe somehow the 12 volt line is getting shorted... I'm just here to take a break from it.
But thing is, I gotta write a book or something. These component values and all that, people give way too much attention to that.
On Wed, 31 Jul 2019 06:26:17 -0700 (PDT), jurb6006@gmail.com wrote:
With a bridge, only 2 diodes on 4 work
** No, they all work.
You got him on semantics, he probably meant "conduct". Sure they are working when they are conducting, but they are also working when not conducting. They are blocking. When they no longer block they are considered not working.
So it preserve diode life.
** False conclusion derived from a false assertion.
Also ignores some logic on the subject. I won't be as mean as you but I will say it - ijiot ! YOU pick the diodes, they don't pick you ! And do you care if the diode is 50 cents or 60 cents ?
I'm surprised I am even here. I did need a bit of a break though. Got any idea why the hell this Carver Receiver (MX-130) turns off the tuner when I turn off the speakers ? I decided to get away from it, and now I think I have a clue, it switches by relay, maybe somehow the 12 volt line is getting shorted... I'm just here to take a break from it.
I had a computer that would reset when I turned off the amplified
speakers before turning off the computer. A small common mode filter
on the amp cured the problem.
But thing is, I gotta write a book or something. These component values and all that, people give way too much attention to that.
Ya think? Generally speaking, they are damn serious when they talk
about "absolute maximum values.."
And when they specify a mosfet (for instance) at a current capacity
that would cause its leads to melt, or unsolder itself from the board
- well then they are lying.
And when they specify a mosfet (for instance) at a current capacity
that would cause its leads to melt, or unsolder itself from the board
- well then they are lying.
I was meaning that at half wave, only 2 diodes work.
For exemple : D1-D3 for +half wave, D2-D4 for -half wave.
In 2 diodes rectifier, the 2 always work.
On Wed, 31 Jul 2019 06:26:17 -0700 (PDT), jurb6006@gmail.com wrote:
With a bridge, only 2 diodes on 4 work
** No, they all work.
You got him on semantics, he probably meant "conduct". Sure they are working when they are conducting, but they are also working when not conducting. They are blocking. When they no longer block they are considered not working.
So it preserve diode life.
** False conclusion derived from a false assertion.
Also ignores some logic on the subject. I won't be as mean as you but I will say it - ijiot ! YOU pick the diodes, they don't pick you ! And do you care if the diode is 50 cents or 60 cents ?
I'm surprised I am even here. I did need a bit of a break though. Got any idea why the hell this Carver Receiver (MX-130) turns off the tuner when I turn off the speakers ? I decided to get away from it, and now I think I have a clue, it switches by relay, maybe somehow the 12 volt line is getting shorted... I'm just here to take a break from it.
I had a computer that would reset when I turned off the amplified
speakers before turning off the computer. A small common mode filter
on the amp cured the problem.
But thing is, I gotta write a book or something. These component values and all that, people give way too much attention to that.
Ya think? Generally speaking, they are damn serious when they talk
about "absolute maximum values.."
And when they specify a mosfet (for instance) at a current capacity
that would cause its leads to melt, or unsolder itself from the board
- well then they are lying.
** All four diodes conduct - half of them during each half cycle.
You want to play words or electronics ?
The claim about extending diode life was bullshit
I never claimed that.
You probably quoted a quote.
Some Fucking Idiot calling itself jurb...@gmail.com wrote:
** All four diodes conduct - half of them during each half cycle.
You want to play words or electronics ?
** There is no mutual exclusion - you fucking moron.
The claim about extending diode life was bullshit
I never claimed that.
** That is why I posted: "The claim" not " Your claim".
I see you have a MASSIVE problem with following the context.
You probably quoted a quote.
** You completely misread and misconstrued.
Simply because YOU are a congenital, mental retard.
FOAD anytime.
...... Phil
Try to understand that I'm French, so English is not my mother language.
Phil Allison a écrit le 14/08/2019 ŕ 02:26 :
Some Fucking Idiot calling itself jurb...@gmail.com wrote:
** All four diodes conduct - half of them during each half cycle.
You want to play words or electronics ?
** There is no mutual exclusion - you fucking moron.
The claim about extending diode life was bullshit
I never claimed that.
** That is why I posted: "The claim" not " Your claim".
I see you have a MASSIVE problem with following the context.
You probably quoted a quote.
** You completely misread and misconstrued.
Simply because YOU are a congenital, mental retard.
FOAD anytime.
...... Phil
You should just killfile Phil. He is a truly sick individual.
He suffers from some sort of mental illness.
On Wed, 19 Feb 2020 23:46:45 -0000, Jasen Betts <jasen@xnet.co.nz> wrote:
On 2020-02-19, Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Wed, 19 Feb 2020 18:54:56 -0000, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2020-02-19 10:43, Commander Kinsey wrote:
Why do (cheap? expensive ones may be better) PC ATX power supplies need
current drawn from the 5V line to make the 12V line work correctly?
I have a PC with 3 graphics cards running scientific applications. I
acquired three old graphics cards that take about 300W each, and have
loads of cheap (CIT) PSUs that are rated at 650W on the 12V line, which
is what those cards use. So I run each card off its own supply. But
the 12V line at no load, or even at 300W, is only giving out 10 to
10.5V. If I attach a small dummy load of an amp or so to the 5V line,
the 12V line suddenly becomes 12V.
Why are the two lines related in any way?
Sorry for the crosspost, I'm not sure which of these groups are active.
A lot of cheap supplies regulate only one output, and rely on
cross-regulation via the transformer to control the others. If the
regulated output isn't loaded, it rises out of spec and so do the others.
Strangely, with no 5V load, I get 5.2V and 10.5V. A small rise and a large drop.
I can't understand why the following happens: No 5V load, 12V is out. Small (2A) 5V load, 12V is ok. Yet if I draw 30A from 5V, the 12V is still ok? How can zero load upset it, but 2A or 30A (big difference) both be ok?
The difference between nothing and 2A is a factor of infinity
The difference between 2A and 20A is only a factor of 10
Actually the fisrt is more like the difference betweem 2mA and 2A
because the internal feedback takes avout 2mA to run the LM431 and the
optocoupler. So going to 2A loads the 5V output by 1000 times more, better
than infinity. but not by much.
If it's going to be so shit, they could have added a dummy load inside the PSU to make it work properly. They could even have it shut off if there was enough external load.
Diode voltage drop is logarythmic vs current so the voltage on the transformer
needed to make 5V on the output is less with a 2mA load than it is with
a 2A load.
On Thu, 20 Feb 2020 00:32:05 -0000, "Commander Kinsey"
CFKinsey@military.org.jp> wrote:
On Wed, 19 Feb 2020 23:31:01 -0000, Jasen Betts <jasen@xnet.co.nz> wrote:
On 2020-02-19, Commander Kinsey <CFKinsey@military.org.jp> wrote:
Why do (cheap? expensive ones may be better) PC ATX power supplies need current drawn from the 5V line to make the 12V line work correctly?
I have a PC with 3 graphics cards running scientific applications. I acquired three old graphics cards that take about 300W each, and have loads of cheap (CIT) PSUs that are rated at 650W on the 12V line, which is what those cards use. So I run each card off its own supply. But the 12V line at no load, or even at 300W, is only giving out 10 to 10.5V. If I attach a small dummy load of an amp or so to the 5V line, the 12V line suddenly becomes 12V.
Why are the two lines related in any way?
because all the output voltages come from taps on the same transformer
and the voltage regulation is applied to the input to that transformer
and the voltage regulation only watches the 5V line.
Ok, but why does current need to be taken from 5V to make the voltage monitor work?
It is designed to be in a computer, and there's always some load on
the 5 V line. It probably didn't seem terribly important to worry
about a high voltage condition where none should ever exist.
Some power supplies sit and oscillate if they don't have a load on the
5 volt line...
I notice my desktop has 5v present on the USB connector even when it
is turned off, turned on, or just in standby. I suspect it may have a
small independent supply to run the USB connectors for power, and
perhaps that also supplies the CMOS memory so the clock and settings
don't drain the battery.
On Wed, 19 Feb 2020 18:45:55 -0000, default <default@defaulter.net> wrote:
On Wed, 19 Feb 2020 15:43:37 -0000, "Commander Kinsey"
CFKinsey@military.org.jp> wrote:
Why do (cheap? expensive ones may be better) PC ATX power supplies need current drawn from the 5V line to make the 12V line work correctly?
I have a PC with 3 graphics cards running scientific applications. I acquired three old graphics cards that take about 300W each, and have loads of cheap (CIT) PSUs that are rated at 650W on the 12V line, which is what those cards use. So I run each card off its own supply. But the 12V line at no load, or even at 300W, is only giving out 10 to 10.5V. If I attach a small dummy load of an amp or so to the 5V line, the 12V line suddenly becomes 12V.
Why are the two lines related in any way?
Sorry for the crosspost, I'm not sure which of these groups are active..
\
There's often a good reason for it. The 5 volt supply is regulated
and the others are not (generally speaking). The feedback path is
from the 5VDC output back to the mains side of the controller.
The others get line (but not load) regulation via the 5V supply
because they share a common transformer. They are also switching
supplies that work at a high frequency so the transformers have fewer
turns of wire and more volts per turn which results in excellent
transformer "regulation."
So on a cheap shit supply, the 5V is guaranteed to be very close to 5V, but the 12V will drop under heavy load?
And on a decent supply like Corsair, they must regulate both seperately?
I still don't understand why the regulation goes to pot when under 1.5A is taken from 5V. It still regulates that 5V perfectly with no load, but the 12V goes wildly wrong. Why does the regulation need current to be flowing through 5V?
On Wednesday, February 19, 2020 at 7:33:30 PM UTC-5, Commander Kinsey wrote:
On Wed, 19 Feb 2020 23:46:45 -0000, Jasen Betts <jasen@xnet.co.nz> wrote:
On 2020-02-19, Commander Kinsey <CFKinsey@military.org.jp> wrote:
On Wed, 19 Feb 2020 18:54:56 -0000, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2020-02-19 10:43, Commander Kinsey wrote:
Why do (cheap? expensive ones may be better) PC ATX power supplies need
current drawn from the 5V line to make the 12V line work correctly?
I have a PC with 3 graphics cards running scientific applications. I
acquired three old graphics cards that take about 300W each, and have
loads of cheap (CIT) PSUs that are rated at 650W on the 12V line, which
is what those cards use. So I run each card off its own supply. But
the 12V line at no load, or even at 300W, is only giving out 10 to
10.5V. If I attach a small dummy load of an amp or so to the 5V line,
the 12V line suddenly becomes 12V.
Why are the two lines related in any way?
Sorry for the crosspost, I'm not sure which of these groups are active.
A lot of cheap supplies regulate only one output, and rely on
cross-regulation via the transformer to control the others. If the
regulated output isn't loaded, it rises out of spec and so do the others.
Strangely, with no 5V load, I get 5.2V and 10.5V. A small rise and a large drop.
I can't understand why the following happens: No 5V load, 12V is out. Small (2A) 5V load, 12V is ok. Yet if I draw 30A from 5V, the 12V is still ok? How can zero load upset it, but 2A or 30A (big difference) both be ok?
The difference between nothing and 2A is a factor of infinity
The difference between 2A and 20A is only a factor of 10
Actually the fisrt is more like the difference betweem 2mA and 2A
because the internal feedback takes avout 2mA to run the LM431 and the
optocoupler. So going to 2A loads the 5V output by 1000 times more, better
than infinity. but not by much.
If it's going to be so shit, they could have added a dummy load inside the PSU to make it work properly. They could even have it shut off if there was enough external load.
Diode voltage drop is logarythmic vs current so the voltage on the transformer
needed to make 5V on the output is less with a 2mA load than it is with
a 2A load.
That is absolutely stupid. A dummy load wastes power, it generates extra heat and the heat shortens the equipment's life.
Those are dedicated power supplies, not bench or lab supplies. They were designed to operate with a minimum load. If you don't like it, go to a four or five output supply with trimmers to calibrate each output. Be prepared to pay $250 to $400 for one.
You bitch about only getting 650 Watts output. Read the specifications. that 850W maximum is fully loading all outputs at the same time. Do yourself a favor and take some basic Electronics classes.
On Wednesday, February 19, 2020 at 1:55:31 PM UTC-5, Commander Kinsey wrote:
On Wed, 19 Feb 2020 18:45:55 -0000, default <default@defaulter.net> wrote:
On Wed, 19 Feb 2020 15:43:37 -0000, "Commander Kinsey"
CFKinsey@military.org.jp> wrote:
Why do (cheap? expensive ones may be better) PC ATX power supplies need current drawn from the 5V line to make the 12V line work correctly?
I have a PC with 3 graphics cards running scientific applications. I acquired three old graphics cards that take about 300W each, and have loads of cheap (CIT) PSUs that are rated at 650W on the 12V line, which is what those cards use. So I run each card off its own supply. But the 12V line at no load, or even at 300W, is only giving out 10 to 10.5V. If I attach a small dummy load of an amp or so to the 5V line, the 12V line suddenly becomes 12V.
Why are the two lines related in any way?
Sorry for the crosspost, I'm not sure which of these groups are active.
\
There's often a good reason for it. The 5 volt supply is regulated
and the others are not (generally speaking). The feedback path is
from the 5VDC output back to the mains side of the controller.
The others get line (but not load) regulation via the 5V supply
because they share a common transformer. They are also switching
supplies that work at a high frequency so the transformers have fewer
turns of wire and more volts per turn which results in excellent
transformer "regulation."
So on a cheap shit supply, the 5V is guaranteed to be very close to 5V, but the 12V will drop under heavy load?
And on a decent supply like Corsair, they must regulate both seperately?
I still don't understand why the regulation goes to pot when under 1.5A is taken from 5V. It still regulates that 5V perfectly with no load, but the 12V goes wildly wrong. Why does the regulation need current to be flowing through 5V?
I didn't read all the answers, so maybe someone said this,
but some SMPS (switch mode PS) topologies have a minimum current.
(Mostly related to keeping current in the inductor.. you could
look up the difference between continuous and discontinuous
conduction modes.
On Wednesday, February 19, 2020 at 11:43:15 AM UTC-8, Commander Kinsey wrote:
The supplies I'm having bother with are not that old, probably 5 years. But they were the second cheapest. They also lie on their specs. They're sold as 850W supplies, but you can only draw 650W of that on the 12V line, which is where 99% of the power goes in a modern PC.
Some modern PCs, sure.
The 'specs' proably told you about that 650W limit, and
that means they were NOT lying.
Nowadays, aren't all the chips running at about 1V and powered by their own VRMs, fed off the 12V line?
Only the CPUs, high-density LSI and some RAM use those low voltages; it's a scaling thing.
with DC/DC converters to provide ALL the ATX
power pins' outputs; you might consider a 12V-only source instead of an ATX supply
https://www.amazon.com/MEAN-WELL-LRS-350-12-Computer-Project/dp/B07VTLJS18