From: bigcat@meeow.co.uk (N. Thornton)
Newsgroups: sci.electronics.design
Subject: Re: Wrestlemania Royale: Tantalum vs. Electrolytic Vs. Polys, etc.
Date: 31 Oct 2002 05:10:16 -0800
Organization: http://groups.google.com/
Message-ID:
References: <3db97370.131896254@news.pacific.net.sg> <3dbaca63.81657086@news.pacific.net.sg> <3dbce44b.14720705@news.pacific.net.sg> <5DlrmiA83Rv9EwCN@jmwa.demon.co.uk> <3dbd4895.40398398@news.pacific.net.sg>
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NNTP-Posting-Date: 31 Oct 2002 13:10:16 GMT
a?n?g?e?l@lovergirl.lrigrevol.moc.com (The little lost angel) wrote in message news:<3dbd4895.40398398@news.pacific.net.sg>...
Hi LA.
Heh, I never want to call you Angel, but you dont give us anything
else to call you! lol. :PPpPppP
>gnd-+--+--+--+--+
> | | | | |
> | R R R R C | | | |
> | L L L L
> | | | | |
>v+--+--+--+--+--+
>
>Which I think is what you are recommending against, since I
>hope to use only one cap, where should I put it, since I can't put it
>in series with any of the Resistor/LED chain, and putting it at the
>end wouldn't be any different from putting it at the front right?
indeed it would. It may well be OK, in fact it almost certainly would,
thinking about it a bit more.
>No regulators, I've gone the way of tapping the +12V line.
thats good.
>>I wouldnt bother about it. At some point you got to ask yourself
what
>>life is all about, and what you want to do with your time, one LEd
>>project or 10 projects that flicker occasionally.
>>
>>And to think you're doing all this for 3 USD! Good luck.
>Well, if I'm going to do something, I'd like to try to make it as
good
>as I can. Plus what I do now, may not be significant for this thing,
>but who knows what I might try next? What I left out or ignore now
>could become a big headache say if I did the same while making my own
>bench PSU.
naaaa, an occasional flicker on a bench PSU's power LED? If you didnt
worry about it you could have built your bench PSU by now!
Way I see it is you've only got one lifetime. I think perfection is
very imperfect. :) In fact I think perfection is an unreal concept, as
perfection means its the best in every way, and that always means self
contradiction. Its not only practically impossible to produce
perfection, its also _conceptually_ impossible.
Think through _exactly_ what a perfect thing would be like, and you
soon see the self contradictory nature of the perfection concept.
NT drifts OT.
>>In that case, your ASCII schematic is correct (but conventionally
upside
>>down; + should be at the top).
>Hee, sorry, I did that looking at my schematic, which had the ground
>trace at the top :P
uhoh, the tongue again. I hope you dont work around EHT with that
tongue of yours! I've never seen a tongue arc before :) I'm thinking
sizzling noises...
>>> where should I put it, since I can't put it
>>>in series with any of the Resistor/LED chain, and putting it at the
>>>end wouldn't be any different from putting it at the front right?
>>
>>Right; you would need four caps, each across one LED
>Hmm, sorry need confirmation, so I can get away with just one cap or
>must I use as many as there are LED? 4 small caps still cost more
than
>1 big cap :D
I reckone one'd do. I also reckon none'd do. Why? Well, you got almst
no load on this PSU, and when its used IRL in a puter it will have to
produce a constant 12v. Otherwise the HDD speed would be all over the
shop, and the machine'd never work. So it must produce constant 12v in
its IRL app. Thats part of the ATX spec as well. So I conclude that
once the PSU is installed there will be no flicker.
>Then again, since I'm testing with almost no load on the +5V, it
could
>simply be the SMPS lapsing into discontinuous mode to protect itself
>in zero load condition.
Exactly, thats what it seems to be doing.
>Ah, yes, you must load the 5 V supply. Put 2.5 ohms 10 W or 5 ohms 5
W
>across it.
or a nice fat 12v bulb would do, more likely to be to hand.
Regards, NT