Electrolytic capacitors

[Peter Howard]

I've just had a tiny triumph by resuscitating a small format ATX PC power
supply, mainly by replacing all the obviously bulged electros first, then
every other electro. All with mail order low-esr types. Fortunately, the
supply was all through hole construction, not SM. Would not have bothered
except that the small format supplies as found in many mini-tower boxes are
considerably more costly than a generic standard sized supply.
Anyway, I've become interested in electros and esr to the extent of buying a
Bob Parker MkII ESR meter kit, on special this month at Tricky Dicks.Still
being assembled.

Questions arise.
(1) I like to have a few dozen common electros on hand in the parts box. All
I can get locally is standard esr types. Anything to be said for paying a
little more and standardizing on low-esr types by mail-order? Is a low-esr
type necessarily better quality and longer lasting?

(2) From studying the RS and Farnell catalogues I notice that they have a
more limited range of low-esr types. For instance, the smallest 10uf type I
find is 25VW versus 16VW for "standard" type. What is the experts practical
experience of selecting working voltage? I Googled the topic and I found
little in the way of practical advice. For instance, if I want to place a
filter cap after a 12v 3term regulator, I'd probably choose one of
appropriate capacitance and 16VW. What about 25VW? Or 35VW or 63VW?
Obviously, I would not use a cap of 300VW as I think I understand that
choosing too high a VW won't permit the dielectric film to be maintained.
What I need is a practical rule-of-thumb.

(3) Lots of my parts box electros are small unsused bargain-bag types up to
5 years old. Should I toss the lot or check them all with the ESR meter and
keep the ones that seem to have "normal" esr compared to a similar factory
fresh one? I also have a capacitance meter so any that are out of tolerance
will be tossed anyway.

(4) I like tantalum caps because they are small and colourful, though I have
read that they are less tolerant of voltage spikes than aluminium electros.
I tend to use them instead of small value electros. Any reason why I should
not?

PH

 

[Phil Allison]

"Peter Howard"

Anyway, I've become interested in electros and esr to the extent of buying
a Bob Parker MkII ESR meter kit, on special this month at Tricky
Dicks.Still being assembled.

** You ought to finish the ESR meter and try it out.

Most of your queries will disappear afterwards.

Questions arise.

(1) I like to have a few dozen common electros on hand in the parts box.
All I can get locally is standard esr types.

** Most recent manufacture electros ARE low ESR.

Certainly all the 105C types are.

The term "low" is relative - ie it means lower than what others are
currently offering.

(2) From studying the RS and Farnell catalogues I notice that they have a
more limited range of low-esr types. For instance, the smallest 10uf type
I find is 25VW versus 16VW for "standard" type.

** So ?

What is the experts practical experience of selecting working voltage? I
Googled the topic and I found little in the way of practical advice. For
instance, if I want to place a filter cap after a 12v 3term regulator, I'd
probably choose one of appropriate capacitance and 16VW. What about 25VW?
Or 35VW or 63VW?

** Finish the damn ESR meter.

Those caps need to be under 2 ohms, ESR.

Obviously, I would not use a cap of 300VW as I think I understand that
choosing too high a VW won't permit the dielectric film to be maintained.

** Plus being silly large.

What I need is a practical rule-of-thumb.

** OK - I can answer that.

Never let yourself get under somebody's thumb.

The Rolling Stones did a great song about it.

(3) Lots of my parts box electros are small unsused bargain-bag types up
to 5 years old. Should I toss the lot or check them all with the ESR meter
and keep the ones that seem to have "normal" esr compared to a similar
factory fresh one?

** Finish the damn ESR meter !

I also have a capacitance meter so any that are out of tolerance will be
tossed anyway.

** If the ESR is OK - so also will be the Faradays.

Finish the damn ESR meter !!

(4) I like tantalum caps because they are small and colourful,

** Bet you just go * ape * over garden gnomes .......

though I have read that they are less tolerant of voltage spikes than
aluminium electros.

** Err - current spikes are their major downfall.

Some are destroyed by a simple short.

I tend to use them instead of small value electros. Any reason why I
should not?

** Yep.

Avoid tants at all costs.




.......... Phil

 

[Parmin]

"Alan Rutlidge" <don't_spam_me_rutlidge@iinet.net.au> while reading
the NewsGroups, found courage and express out opinion in
news:43eb4483$0$3654$5a62ac22@per-qv1-newsreader-01.iinet.net.au:

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:450ttrF4ctilU1@individual.net...


Avoid tants at all costs.

Shouldn't that read "Avoid Phil's tantrums at all costs."?






......... Phil

err.. tantharums

 

[Ed -]

add to your list of tests: check leakage after a min or so on a dc
voltage
high temp electros are supposed to be longer lasting ie: 105 -v- 85 deg
C


"Peter Howard" <bbrover109@bbbigpond.net.au> wrote in message
news:lgGGf.2705$yK1.2279@news-server.bigpond.net.au...
: I've just had a tiny triumph by resuscitating a small format ATX PC
power
: supply, mainly by replacing all the obviously bulged electros first,
then
: every other electro. All with mail order low-esr types. Fortunately,
the
: supply was all through hole construction, not SM. Would not have
bothered
: except that the small format supplies as found in many mini-tower
boxes are
: considerably more costly than a generic standard sized supply.
: Anyway, I've become interested in electros and esr to the extent of
buying a
: Bob Parker MkII ESR meter kit, on special this month at Tricky
Dicks.Still
: being assembled.
:
: Questions arise.
: (1) I like to have a few dozen common electros on hand in the parts
box. All
: I can get locally is standard esr types. Anything to be said for
paying a
: little more and standardizing on low-esr types by mail-order? Is a
low-esr
: type necessarily better quality and longer lasting?
:
: (2) From studying the RS and Farnell catalogues I notice that they
have a
: more limited range of low-esr types. For instance, the smallest 10uf
type I
: find is 25VW versus 16VW for "standard" type. What is the experts
practical
: experience of selecting working voltage? I Googled the topic and I
found
: little in the way of practical advice. For instance, if I want to
place a
: filter cap after a 12v 3term regulator, I'd probably choose one of
: appropriate capacitance and 16VW. What about 25VW? Or 35VW or 63VW?
: Obviously, I would not use a cap of 300VW as I think I understand that
: choosing too high a VW won't permit the dielectric film to be
maintained.
: What I need is a practical rule-of-thumb.
:
: (3) Lots of my parts box electros are small unsused bargain-bag types
up to
: 5 years old. Should I toss the lot or check them all with the ESR
meter and
: keep the ones that seem to have "normal" esr compared to a similar
factory
: fresh one? I also have a capacitance meter so any that are out of
tolerance
: will be tossed anyway.
:
: (4) I like tantalum caps because they are small and colourful, though
I have
: read that they are less tolerant of voltage spikes than aluminium
electros.
: I tend to use them instead of small value electros. Any reason why I
should
: not?
:
: PH
:
:
:

 

[Mark Harriss]

Alan Rutlidge wrote:

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:450ttrF4ctilU1@individual.net...

Avoid tants at all costs.


Shouldn't that read "Avoid Phil's tantrums at all costs."?






......... Phil







I thought his lithiums were charged, not his tantalums

 

[Terry Given]

Peter Howard wrote:

I've just had a tiny triumph by resuscitating a small format ATX PC power
supply, mainly by replacing all the obviously bulged electros first, then
every other electro. All with mail order low-esr types. Fortunately, the
supply was all through hole construction, not SM. Would not have bothered
except that the small format supplies as found in many mini-tower boxes are
considerably more costly than a generic standard sized supply.
Anyway, I've become interested in electros and esr to the extent of buying a
Bob Parker MkII ESR meter kit, on special this month at Tricky Dicks.Still
being assembled.

Questions arise.
(1) I like to have a few dozen common electros on hand in the parts box. All
I can get locally is standard esr types. Anything to be said for paying a
little more and standardizing on low-esr types by mail-order? Is a low-esr
type necessarily better quality and longer lasting?

generally, yes. electro's age by boiling off their electrolyte (so dont
place them beside hot things). low ESR = low internal losses, hence
longer lifetime. also decent low ESR caps specify lifetime, ripple
current and ESR, whereas crappy caps dont specify much of anything.

you do need to pay attention with 50/60Hz rectifier caps though, as
ripple current ratings are generally 30% lower at 120Hz than 100kHz.

OTOH some circuits require a nice, high ESR - LDO regulators are a good
example, many need 1-5 ohms ESR, in which case a "crappy" electro is a
better choice than a "good" (low ESR) cap.

conversely, I once used a 10uF 16V smt electro with 27 ohms ESR, it was
supposed to stop a TL431 reference oscillating, and did the exact opposite.

(2) From studying the RS and Farnell catalogues I notice that they have a
more limited range of low-esr types. For instance, the smallest 10uf type I
find is 25VW versus 16VW for "standard" type. What is the experts practical
experience of selecting working voltage? I Googled the topic and I found
little in the way of practical advice. For instance, if I want to place a
filter cap after a 12v 3term regulator, I'd probably choose one of
appropriate capacitance and 16VW. What about 25VW? Or 35VW or 63VW?
Obviously, I would not use a cap of 300VW as I think I understand that
choosing too high a VW won't permit the dielectric film to be maintained.
What I need is a practical rule-of-thumb.

as the voltage applied to an electro cap reduces, the cap lifetime
increases - up to a point, so this is one reason to choose a
higher-voltage cap. it stops helping at 70% or so of rated voltage though.

when I design in an electrolytic cap, I normally know what voltage,
ripple current and temperature the cap will see, and roughly how much
capacitance I want - but more usually how much ripple voltage I want.
The voltage spec is used to pick a minimum cap voltage. the current and
voltage ripple give an idea of the required capacitance and ESR, then I
go looking for the cheapest cap that fits the bill.

often mechanical constraints dictate the cap I pick....

(3) Lots of my parts box electros are small unsused bargain-bag types up to
5 years old. Should I toss the lot or check them all with the ESR meter and
keep the ones that seem to have "normal" esr compared to a similar factory
fresh one? I also have a capacitance meter so any that are out of tolerance
will be tossed anyway.

I have a whole draw full of them (Jaycar mixed bags, among others), they
are OK as long as you know their limitations.

(4) I like tantalum caps because they are small and colourful, though I have
read that they are less tolerant of voltage spikes than aluminium electros.
I tend to use them instead of small value electros. Any reason why I should
not?

PH

if you look at the lifetime calcs for tants, you will see they are a LOT
more sensitive to being operated near their rated voltage - I havent
designed one into a circuit for 10yrs now, but ISTR you want to run them
at about 70% of rated voltage. If you abuse a tant, it will fail
catastrophically, and MnO2 tants can explode all on their own, too.

Cheers
Terry

 

[The Real Andy]

On Mon, 13 Feb 2006 10:50:38 +1100, "Phil Allison"
<philallison@tpg.com.au> wrote:

"Chris Jones"

I found that
the 105 degree caps seem to have a significantly higher ESR than 85 degree
C ones, so I have stopped my habit of automatically fitting the 105
degree...


** If electro caps are deteriorating and needing replacement - then it
is *odds on* they are operating in a hot environment. So 105 C types
will
likely last much longer than the 85 C types.

Also be aware that the ESR of an electro goes DOWN when the cap gets hot
- by a factor of up to 5 times !!!



The point I was making is that the ESR of the 105 degree types was several
times larger than that of the 85 degree type from the same manufacturer,
when I measured it.


** Shame you did not say *that* before.

Kindly post the revalant info - ie cap maker, ratings, physical size &
actual ESR readings.

In many years of checking electros I have NOT come across anything like
your claim.



Therefore in some applications where ESR really
matters e.g. SMPS output, it is possible that after replacing the caps
with
higher temperature types, the thing will not work as well as it would have
done if the 85 degree type had been used, and in the worst case, the 105
degree caps could heat up more than twice as much as the 85 degree type,
and could exceed 105 degrees in a situation where the 85 degree caps would
have stayed below 85 degrees C.


** You are making this all up as you go along.

Electros are not operated at such high temps in SMPSs.

Phil the God and creator of all SMPS's on this would know.

........... Phil

 

[Phil Allison]

"The Real Andy"



** Shame Andy has run out of public toilets to troll.

Maybe he will stalk the ones at the local primary next.





......... Phil

 

[The Real Andy]

On Tue, 14 Feb 2006 10:42:57 +1100, "Phil Allison"
<philallison@tpg.com.au> wrote:

"The Real Andy"



** Shame Andrew Pearson has run out of public toilets to troll.

Maybe he will stalk the ones at the local Brisbane primary next.

Shame Phli Allison the worn out uni reject roadie has run out of
lines.

 

[Phil Allison]

"The Real Andy"



** I know where you work - you fucking alcoholic idiot.

How about I speak to your employer and get you dismissed ?






......... Phil

 

[The Real Andy]

On Tue, 14 Feb 2006 20:59:20 +1100, "Phil Allison"
<philallison@tpg.com.au> wrote:

"The Real Andy"



** I know where you work - you fucking alcoholic idiot.

How about I speak to your employer and get you dismissed ?

Dismissed for what? Proving you are an idiot? Pffft. By the way, i
work for myself now. Try again fool.

 

[Phil Allison]

"Alan Rutlidge"


** There are lots of *folk* out there, Alan, who would really *despise* a
49 year old ,Telstra faggot who openly engage in sex tourism in Asia.

Aside from the fact it has long been a serious criminal offence.

You need to wake up just how vulnerable you are.





........ Phil

 

[Alan Rutlidge]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:45e4ojF6a6dgU1@individual.net...

"Alan Rutlidge"


** There are lots of *folk* out there, Alan, who would really *despise*
a 49 year old ,Telstra faggot who openly engage in sex tourism in Asia.

Aside from the fact it has long been a serious criminal offence.

You need to wake up just how vulnerable you are.





....... Phil

Vulnerable to what Phil? Your bullshit?

ROFLMAO

 

[Alan Rutlidge]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:45e4a9F68lrkU1@individual.net...

"The Real Andy"

= a Drunk as a Skunk Cunthead


** I know where you work - you fucking alcoholic idiot.

How about I speak to your employer and get you dismissed ?


Dismissed for what? Proving you are an idiot? Pffft. By the way, i
work for myself now.



** So your long suffering employers at " Jupiters Technology " in
Brisbane OBVIOUSLY had had a massive, fucking gutful of your
fuckhead drunk behaviour while at work.

Not to mention the fact you are a dumb as fucking dog shit
*electrician puke* pretending to be an " ingineuer ".

So they finally woke up an gave you the BOOT !!!

ROTFL

How time wounds all heels !!!





........ Phil

So what does that say about you? Self employed Toaster Boi?

Only a dipstick would employ you (Mr. Charisma) or someone who deliberately
wanted to run their business as a tax dodge. With you in the picture, any
venture would be doomed to failure.

BTW, how do you manage to get by on that less than $50,000 gross turnover
non-GST reporting "business" of yours? I've done the sums and in
consideration that you rent that dump of a bed-sit flat which is also your
place of business you must be surviving on handouts from the Salvos. Either
that or you're collecting CentreLink benefits and / or falsely declaring
your income?

So just how do you get by Phil? I'm sure we'd all be interested to know how
you do it.

 

[Phil Allison]

"Chris Jones"

What is now clear to me is that there are so many different types in both
temperature ranges that it would not be surprising if there were some high
and low ESR grades in both ranges and therefore the possibility of me
finding high temperature ones that happen to be from a series which
doesn't
have as good ESR as some of the low temperature grades. The lesson that I
learnt was that I should measure the ESR and not assume any temperature
range are always better.

** Nor falsely assume that temp grade and ESR go hand in hand.

Therefore in some applications where ESR really
matters e.g. SMPS output, it is possible that after replacing the caps
with
higher temperature types, the thing will not work as well as it would
have done if the 85 degree type had been used, and in the worst case,
the
105 degree caps could heat up more than twice as much as the 85 degree
type, and could exceed 105 degrees in a situation where the 85 degree
caps would have stayed below 85 degrees C.


** You are making this all up as you go along.

Well I have never seen it happen so yes if you like, but certainly a
capacitor with high ESR could be heated quite a bit when subjected to a
few
amps of ripple current.

** Shame how the ESR falls as the electrolyte heats up.

Electros are not operated at such high temps in SMPSs.

Hopefully not, in a good design, but then I probably wouldn't be trying to
fix it if it had been designed properly.

** You got a diploma in Pure and Applied Guesswork ???

Or still working on that.



......... Phil

 

[Phil Allison]

"Terry Given"

(snip drivel)


** Terry is one of those studious guys who wrote brilliant answers to every
exam questions he faced - but was then marked 1 or 2 out of 10 for them.

Because what Terry wrote did NOT answer the question as posed.

No insight.

At all.



......... Phil

 

[Terry Given]

Phil Allison wrote:

"Terry Given"

(snip drivel)


** Terry is one of those studious guys who wrote brilliant answers to every
exam questions he faced - but was then marked 1 or 2 out of 10 for them.

Phil said it, so it must be true.

Because what Terry wrote did NOT answer the question as posed.

No insight.

At all.

........ Phil

Well done Phil, not a single piece of invective.

Cheers
Terry

 

[David Sauer]

On Thu, 09 Feb 2006 12:07:45 GMT, in aus.electronics you wrote:

Anyway, I've become interested in electros and esr to the extent of buying a
Bob Parker MkII ESR meter kit, on special this month at Tricky Dicks.Still
being assembled.

IIRC always make sure the caps are discharged before putting the meter
on it. It's not designed to discharge a 300V cap.

Bob Barker frequents here occasionally if you have any issues with it.

 

[Bob Parker]

Bob Barker hosts/hosted a US TV show. Bob Parker designed the ESR
meter.




On Fri, 24 Feb 2006 18:32:43 +1000, David Sauer
<davidsauer@iinet.net.au> wrote:

On Thu, 09 Feb 2006 12:07:45 GMT, in aus.electronics you wrote:

Anyway, I've become interested in electros and esr to the extent of buying a
Bob Parker MkII ESR meter kit, on special this month at Tricky Dicks.Still
being assembled.

IIRC always make sure the caps are discharged before putting the meter
on it. It's not designed to discharge a 300V cap.

Bob Barker frequents here occasionally if you have any issues with it.

 

[Terry Given]

Bob Parker wrote:

Bob Barker hosts/hosted a US TV show. Bob Parker designed the ESR
meter.




On Fri, 24 Feb 2006 18:32:43 +1000, David Sauer
davidsauer@iinet.net.au> wrote:


On Thu, 09 Feb 2006 12:07:45 GMT, in aus.electronics you wrote:


Anyway, I've become interested in electros and esr to the extent of buying a
Bob Parker MkII ESR meter kit, on special this month at Tricky Dicks.Still
being assembled.

IIRC always make sure the caps are discharged before putting the meter
on it. It's not designed to discharge a 300V cap.

Bob Barker frequents here occasionally if you have any issues with it.

Hi Bob,

what frequency do you test ESR at?

Cheers
Terry