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Mike Raiford wrote:
>> Hmm. I thought that was the design goal of a capacitor?
>>
>
> In the case of the capacitor storing the energy for a flash, flash
> discharges are actually rather finely timed. Something to the effect of
> 1 millisecond for a full-power flash, this discharges the capacitor
> quickly, but not instantly. Lower power strobes only allow a partial
> discharge at the same rate, which is why recycle time is much quicker
> when using a flash at a lower power, because the cap isn't empty.
> Shorting a capacitor without a resistor allows high amounts of current
> to flow, which can cause an arc across the dielectric, thus destroying
> the capacitor. At least that's how I understand it.
>
> In other applications, discharge is much slower, such as when they are
> used to smooth ripple current from a DC power supply.
...and here I was thinking they use capacitors to tune MHz-frequency
oscilators...
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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On Wed, 06 Feb 2008 14:12:01 +0000, Bill Pragnell <bil### [at] hotmail com>
wrote:
>
>Are you sure it wasn't you who threw the screwdriver across the room?
>;-) I know I would have!
It might have been, it was over 30 years go. I do remember I bounced it off the
terminals and it bounced back a lot further than I expected and left my hand. It
was lucky that no one was standing behind me at the time. Now I take into
account what my reactions might be if something like that happens.
Reactions can be hard to control. When you are working with electricity you
expect shocks and are quick to move. But sometimes it is better not to move as
you could be putting yourself into danger say by moving it against other live
terminals or ripping the skin off on sharp objects. One rule is to always be
insulated from the ground and another rule is to keep one hand in your pocket.
Never hold onto the side of an enclosure for balance don't let the electricity
escape to ground through your body especially if the path could be across your
heart. Also be aware of the differences between AC and DC. AC throws you off DC
can make you grab hold.
One other word of wisdom. Don't urinate on a sub-power station or transformer.
(It was been done.)
Regards
Stephen
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On Wed, 06 Feb 2008 08:10:29 -0600, Mike Raiford <mra### [at] hotmailcom> wrote:
>
>In other applications, discharge is much slower, such as when they are
>used to smooth ripple current from a DC power supply.
If the cap is across the supply and ground then it is acting as a short circuit
to AC but a block to DC.These caps generally have a discharging resistor > 1 meg
across them to slowly discharge it when there is no power applied.
Regards
Stephen
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On Wed, 06 Feb 2008 14:31:20 +0000, Invisible <voi### [at] devnull> wrote:
>...and here I was thinking they use capacitors to tune MHz-frequency
>oscilators...
All oscillators unless you are using chokes or resistors for the variable. :)
Regards
Stephen
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On Wed, 06 Feb 2008 14:42:36 +0000, Stephen <mcavoysATaolDOTcom@> wrote:
>On Wed, 06 Feb 2008 14:31:20 +0000, Invisible <voi### [at] devnull> wrote:
>
>>...and here I was thinking they use capacitors to tune MHz-frequency
>>oscilators...
>
>All oscillators unless you are using chokes or resistors for the variable. :)
>
Hm! Not true I forgot about pneumatic or hydraulic oscillators. Then you would
use reservoirs.
Regards
Stephen
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And lo on Wed, 06 Feb 2008 11:50:05 -0000, Invisible <voi### [at] devnull> did
spake, saying:
> Phil Cook wrote:
>
>> Succinctly put thank you. The whole thing is why hasn't the
>> slot-together style reached down into the standard market, and if it
>> did how would that affect 'normal' users' computer buying patterns.
>> Instead of buying an entire new computer would they instead opt to
>> upgrade the old one because it's a piece of cake to do.
>
> Currently manufacturers assume that the only reason you could want to be
> able to replace parts "easily" is because you need to do it fast, and if
> you need to do it fast it must be because you have a "high availability"
> setup. And if that's the case, the cost of downtime dwarfs any hardware
> price you can come up with. These types of people will pay through the
> nose to avoid downtime - and so that's what gets charged.
Agreed it requires a separation of that concept
> In fairness, it's much harder to design hardware this way. Current
> hardware is "easy enough" that most people can manage it, and there's no
> real large pressure for that to change.
But there should be. From the hardware side a much easier to install
system means cutting out the middle-men of computer dealers and selling
direct to the consumer. Sure you don't get the high volume sales, but
conversely you don't have the high volume discounts. You can sell less for
more.
From the consumers side it makes life easier to upgrade a machine without
considering an entire new box, encourages greater competition between
hardware providers. Plus the older parts can be recycled into older
machines more easily rather then an entire box beig scrapped.
The only ones who wouldn't like it are those who charge a premium for
assembling these products for you.
>> I mean seriously I've listened to friends talking about upgrading their
>> entire computer to get more speed out of a game or something when all
>> they need to do is switch the video card (or *to* a video card rather
>> then the MB GPU). To them the computer is a lump like a television,
>> opening the case doesn't occur to them and I don't think they'd be
>> enthused by what they'd find if they did.
>
> Heh. I bet the hardware guys would want to prevent that. ;-)
They're fast-food chains. Sure you can buy all the same (better)
ingredients yourself, sure you can prepare and cook it yourself, but what
a hassle when you can just walk into an outlet and by the 'same' thing all
ready for you. Now make it much much easier for the consumer to buy and
prepare exactly the same thing for themselves.
> In fairness, if you want to replace the CPU, you will probably end up
> having to replace virtually the entire PC anyway.
If you have a motherboard fitted with an Athlon XP 1500+ you can switch if
for an Athlon XP 3100+ which would be a major jump, it's only if you're
switching from one 'type' to another that you would need to change the
motherboard.
> (You'll almost certainly need a new motherboard and new RAM. And
> replacing a motherboard is currently *hard*. So many things to
> disconnect and reconnect. I especially enjoy playing with the header
> pins for the front plate...)
Ah let's see
PLED+ PLED- PWRBTN# GND
HDLED+ HDLED- GND RSET# DUMMY
and the front USB connectors
USB_PWR P-5 P+5 GND DUMMY
USB_PWR P-4 P+4 GND
so I've a white , green, black, and white set of separate connectors
(IIRC) so this helps me how? Seriously can you imagine if a non-tech tried
to do this, imagine if they had to play match the wires for every USB
device they plugged in. Oops silly me all this is detailed in the case
manual... now what did I do with that?
--
Phil Cook
--
I once tried to be apathetic, but I just couldn't be bothered
http://flipc.blogspot.com
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>> Currently manufacturers assume that the only reason you could want to
>> be able to replace parts "easily" is because you need to do it fast,
>> and if you need to do it fast it must be because you have a "high
>> availability" setup. And if that's the case, the cost of downtime
>> dwarfs any hardware price you can come up with. These types of people
>> will pay through the nose to avoid downtime - and so that's what gets
>> charged.
>
> Agreed it requires a separation of that concept
Indeed.
>> In fairness, it's much harder to design hardware this way. Current
>> hardware is "easy enough" that most people can manage it, and there's
>> no real large pressure for that to change.
>
> But there should be. From the hardware side a much easier to install
> system means cutting out the middle-men of computer dealers and selling
> direct to the consumer. Sure you don't get the high volume sales, but
> conversely you don't have the high volume discounts. You can sell less
> for more.
Yeah, well, until the idea reaches the people who can make it happen.
Oh, and somebody comes up with a *standard* system... and everybody
actually *uses* it... These are the main barriers, I think.
> From the consumers side it makes life easier to upgrade a machine
> without considering an entire new box, encourages greater competition
> between hardware providers. Plus the older parts can be recycled into
> older machines more easily rather then an entire box beig scrapped.
>
> The only ones who wouldn't like it are those who charge a premium for
> assembling these products for you.
AFAIK, manufacturers want to *reduce* competition, not increase it. ;-)
>> In fairness, if you want to replace the CPU, you will probably end up
>> having to replace virtually the entire PC anyway.
>
> If you have a motherboard fitted with an Athlon XP 1500+ you can switch
> if for an Athlon XP 3100+ which would be a major jump, it's only if
> you're switching from one 'type' to another that you would need to
> change the motherboard.
Maybe it's just me, but I wouldn't pay several hundred pounds for a new
component unless it yields a *massive* performance increase. And that
virtually guarantees that it's going to be a completely different CPU
socket...
> so I've a white , green, black, and white set of separate connectors
> (IIRC) so this helps me how? Seriously can you imagine if a non-tech
> tried to do this, imagine if they had to play match the wires for every
> USB device they plugged in. Oops silly me all this is detailed in the
> case manual... now what did I do with that?
If you can show me a motherboard manual that *isn't* translated from
Tiawaniis by Google Translate, I'd consider buying that motherboard! ;-)
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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And lo on Wed, 06 Feb 2008 15:17:31 -0000, Invisible <voi### [at] devnull> did
spake, saying:
>>> In fairness, it's much harder to design hardware this way. Current
>>> hardware is "easy enough" that most people can manage it, and there's
>>> no real large pressure for that to change.
>> But there should be. From the hardware side a much easier to install
>> system means cutting out the middle-men of computer dealers and selling
>> direct to the consumer. Sure you don't get the high volume sales, but
>> conversely you don't have the high volume discounts. You can sell less
>> for more.
>
> Yeah, well, until the idea reaches the people who can make it happen.
> Oh, and somebody comes up with a *standard* system... and everybody
> actually *uses* it... These are the main barriers, I think.
Inertia, we need a halfway house. A motherboard manufacturer creates the
standard system and offers cases that allow the current standard of video
cards/CPUs etc. to be used.
>> From the consumers side it makes life easier to upgrade a machine
>> without considering an entire new box, encourages greater competition
>> between hardware providers. Plus the older parts can be recycled into
>> older machines more easily rather then an entire box beig scrapped.
>> The only ones who wouldn't like it are those who charge a premium for
>> assembling these products for you.
>
> AFAIK, manufacturers want to *reduce* competition, not increase it. ;-)
Hence my splitting up into consumer and manufacturer arguments :-)
>>> In fairness, if you want to replace the CPU, you will probably end up
>>> having to replace virtually the entire PC anyway.
>> If you have a motherboard fitted with an Athlon XP 1500+ you can
>> switch if for an Athlon XP 3100+ which would be a major jump, it's only
>> if you're switching from one 'type' to another that you would need to
>> change the motherboard.
>
> Maybe it's just me, but I wouldn't pay several hundred pounds for a new
> component unless it yields a *massive* performance increase. And that
> virtually guarantees that it's going to be a completely different CPU
> socket...
Except then you're not paying several hundred pounds for a CPU you're
paying several hundred pounds for a CPU, a motherboard, and memory. If you
for that motherboard may be just the thing.
>> so I've a white , green, black, and white set of separate connectors
>> (IIRC) so this helps me how? Seriously can you imagine if a non-tech
>> tried to do this, imagine if they had to play match the wires for every
>> USB device they plugged in. Oops silly me all this is detailed in the
>> case manual... now what did I do with that?
>
> If you can show me a motherboard manual that *isn't* translated from
> Tiawaniis by Google Translate, I'd consider buying that motherboard! ;-)
This one was surprisingly good it was the Technanese that could have been
a problem.
"3. Hold components by the edges and do not touch the ICs."
Don't touch the what now?
and my favourite
"... a multimedia PC-DIY live demo, which shows you how to install your
own PC system step by step... You can find the file in the Support CD..."
So I'm building my first computer from scratch and they want to me to
watch a video on the CD that's telling me how to install the components so
I can watch this video?
--
Phil Cook
--
I once tried to be apathetic, but I just couldn't be bothered
http://flipc.blogspot.com
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> and my favourite
>
> "... a multimedia PC-DIY live demo, which shows you how to install your
> own PC system step by step... You can find the file in the Support CD..."
>
> So I'm building my first computer from scratch and they want to me to
> watch a video on the CD that's telling me how to install the components
> so I can watch this video?
Infinite recursion error! :-D
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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And lo on Wed, 06 Feb 2008 15:49:17 -0000, Invisible <voi### [at] devnull> did
spake, saying:
>> and my favourite
>> "... a multimedia PC-DIY live demo, which shows you how to install
>> your own PC system step by step... You can find the file in the Support
>> CD..."
>> So I'm building my first computer from scratch and they want to me to
>> watch a video on the CD that's telling me how to install the components
>> so I can watch this video?
>
> Infinite recursion error! :-D
FTW
--
Phil Cook
--
I once tried to be apathetic, but I just couldn't be bothered
http://flipc.blogspot.com
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