What qualifies a capacitor as "computer grade"?

[G]

Do they have low ESR and quick recovery?

G

 

[till]

try to search, this was allready diskussed some time ago.

 

[peranders]

They are big, can dissipate much heat (much current), lasts long due to much electrolythic, are reliable.

In short: they are made for heavy duty applications, like high power supplies.

 

[hifi]

As found in all computers =) ....

well in the time before switching supplies anway.....

/micke

 

[Dozuki]

Out of curiosity, when (approximately) did computer manufacturers swithch over to switching supplies?

-D.

(I have yet to see a big can in any computer I've cracked open, huge- ancient HDs, but no cans)

 

[Lisandro_P]

Um... i think PC's have been carrying switched power supplies since they become "personal" (that's it, not occupying a whole room ).

 

[roddyama]

Gavin,

Here is a good place to start. Take a look at this link.
http://www.capacitors.com/pickcap/pickcap.htm

Than you can do some searches on this site and see what's being said about different capacitors. You'll have to make your own jugements from there.

Rodd Yamashita

 

[Fred Dieckmann]

"computer grade"?

What qualifies a capacitor as "computer grade"?
Simple....certification as kosher by a computer Rabi.

Actually the Peranders answer pretty well spells it out. I don't know that there is a set of actual engineering parameters, although capacitor lifetime and 105 degree centigrade rating would be good indicators. Capacitors designed for swiching power supplies have low ESR and low indutance and are usually excellent choices for audio circuits and especially power supplies. This was also true with photo flash capacitors a few years. The new technology of organic semiconductor capacitor are becoming produced by several manufacturers and are exceptional power supply capacitors.

Why does the term "computer grade" evoke the following terms for the cynic in me?

'" Industrial Strength"
"New and Improved"
"Advanced'
"New formula"
"Extra Strength"
"Delux"
"Now with (insert tradename here)"
" Now with 20% more ....."
"Controlled release"
" the most powerful .... that you can get withou a prescription"

Shalom y'all,
Fred

 

[jh6you]

Gee...
The 16:9 was better IMHO.

JH

 

[peranders]

Re: "computer grade"?

Actually the Peranders answer pretty well spells it out. I don't know that there is a set of actual engineering parameters, although capacitor lifetime and 105 degree centigrade rating would be good indicators. Capacitors designed for swiching power supplies have low ESR and low indutance and are usually excellent choices for audio circuits and especially power supplies.

Sometimes I wonder if pcb mounted heavy duty caps are better than these big mamas, with long wires. Computer grade caps (those we talk about here, big with screw connections) are never(?) seen in amps. Has anyone seen classical computer grade caps in a commercial amp (except for Bladelius Designs Group)?

 

[hifi]

yes several times. sometimes with wires sometimes mounded with screws to PCB (sometimes the caps support the PCB there mounted on)

/micke

 

[Fred Dieckmann]

Screw terminal caps CG caps

"Computer grade caps (those we talk about here, big with screw connections) are never(?) seen in amps. Has anyone seen classical computer grade caps in a commercial amp."

Surely you are joking right.......

I would say that the ratio of CG screw terminal capped amps to PCB soldered lug caps is about 50 to one, of what I have seen(for big amps over, say 50 watts per channel)

You must be having a little fun with us. What is Svensk for practical joke.

Screwed down tight,
Fred

 

[UrSv]

I second that. I've seen lots of them in commercial amps. Last one I owned was the Acurus A250.

/UrSv

 

[peranders]

Re: Screw terminal caps CG caps

I would say that the ratio of CG screw terminal capped amps to PCB soldered lug caps is about 50 to one, of what I have seen(for big amps over, say 50 watts per channel)

I gather you are refering to high-end gear. I ment in general. You mean that only 2% of the amps don't have these caps?

FYI: Practical joke is in fact "practical joke" in swedish, never guessed it?

 

[Fred Dieckmann]

I gather you are refering to high-end gear.

Not really... midfi and many of the larger japanese amps also.

Skol
Fred

P.S. Extreme filter cap modification by friend.

 

[hifi]

as an example check rotel. they are midfi...

/micke

 

[jh6you]

Beutiful amp!
I have similar one having serial no. 12s34h45i67t89s.

JH

 

[peranders]

Re: I gather you are refering to high-end gear.

Skol
Fred

You have to practice more.... Skål! Å= ou in thought

 

[crown300]

Or at some point is a Big Hulking Cap with 6" long wire leads equal to a Smaller PCB mount cap located on the circuit board?
(does the higher ESR and lead inductance of the big cap get negated by small cap with low ESR?)
johnm

 

[moses]

Most of your late 70s minicomputers/microcomputers all used switching power supplies. However switching power supplies can still have computer grade caps. The picture shows a couple of large computer grade caps from a minicomputer circa 1984, with a switching power supply. I believe the power supply puts out somewhere in the 75A-90A range, at 5 volts.

An externally hosted image should be here but it was not working when we last tested it.