Electrolytic caps in series

[Mark Harriss]

Rheilly Phoull wrote:

OK, since you guys say you have the real 'gen' (not like Phil) and all the
knowledge, how do ya calculate the values of the resistors ??
Forget all the abuse and denigration, share your superior knowledge with me
??

--
Regards ..... Rheilly Phoull

For resistors across electros in series??: it's in that link I posted.
for resistors in series it's R(total)= r1+r2+r3......+rn
for resistors in parallel it's R(total) = 1/(1/r1 + 1/r2 + 1/r3 +..1/rn)

Regards
Mark

 

[Phil Allison]

"Mark Harriss"

Rheilly Phoull wrote:

OK, since you guys say you have the real 'gen' (not like Phil) and all
the
knowledge, how do ya calculate the values of the resistors ??
Forget all the abuse and denigration, share your superior knowledge with
me
??


For resistors across electros in series??: it's in that link I posted.
for resistors in series it's R(total)= r1+r2+r3......+rn
for resistors in parallel it's R(total) = 1/(1/r1 + 1/r2 + 1/r3 +..1/rn)

Regards
Mark

** Totally asinine shite - as expected from a 20 -ish Neo Nazi Cunt
from Queensland.

Harrarse is functionally illiterate.




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

 

[Mark Harriss]

Phil Allison wrote:

** Totally asinine shite - as expected from a 20 -ish Neo Nazi Cunt
from Queensland.

Harrarse is functionally illiterate.

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

Those formulae are wrong Phil??. How??, Oh sorry I forgot
they most likely ARE different on planet Phil-Toaster-Bitch
Allison!. How DID you arrive at the age of 20 something
anyway? I've worked professionally in electronics for 24
years now: according to your math (Honours) I'm 5 years or
younger when I started in electronics: must have been born
with an iron in my hand eh?.

Hey...good news!!! I've been approached to do honours as
well!!!....isn't that fantastic??. And I got laid yet again!!
The only way we'd have anything in common would be if I
shaved my cat's arsehole and taught it to walk backwards:
Then it would look like you!!!.


Regards
Mark

 

[Phil Allison]

"Mark Harriss"

Phil Allison wrote:

** Totally asinine shite - as expected from a 20 -ish Neo Nazi Cunt
from Queensland.

Harrarse is functionally illiterate.



Those formulae are wrong Phil??.

** Totally asinine shite - as expected from a 20 -ish Neo Nazi Cunt
from Queensland. Harrarse is functionally illiterate.

How DID you arrive at the age of 20 something
anyway?

" Well I should graduate in six months time.......
AND I got laid last night.

Regards Mark "

I've worked professionally in electronics for 24
years now:

** Without learning a single, damn thing - must qualify for a
stupidity award.

Hey...good news!!! I've been approached to do honours as well!!!....isn't
that fantastic??. And I got laid yet again!!

** Gay sex does not count - you pathetic, fascist, autistic moron.





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

 

[KLR]

The only way we'd have anything in common would be if I
shaved my cat's arsehole and taught it to walk backwards:
Then it would look like you!!!.

A cat's arse hole doesnt have any hair on it.

Regards
Mark

 

[Mark Harriss]

KLR wrote:

The only way we'd have anything in common would be if I
shaved my cat's arsehole and taught it to walk backwards:
Then it would look like you!!!.


A cat's arse hole doesnt have any hair on it.

Regards
Mark


You haven't seen my cat then: a very hairy date!!

 

[David L. Jones]

Rheilly Phoull wrote:

OK, since you guys say you have the real 'gen' (not like Phil) and all the
knowledge, how do ya calculate the values of the resistors ??
Forget all the abuse and denigration, share your superior knowledge with me
??

--
Regards ..... Rheilly Phoull

What you do is calculate the bleeder resistor value based on the
following worst case conditions:
- The maximum voltage rating of one one of the caps
- Assuming one cap has maximum leakage and the other has zero leakage

i.e. The capacitor with the leakage with drag the mid rail voltage away
from it's nominal half rail, creating a greater voltage across the cap
with no leakage. You don't want to have more than the maximum capacitor
voltage across the non-leaky cap.

Once you assume these worse case conditions then the circuit is easy to
analyse.

Each resistor is:
R=(CapLeakRes * (MaxCapVolt-(Vrail/2)) / (Vrail-MaxCapVolt)) * 2

The leakage will be voltage dependant, but this a simple way to look at
it.

Hope that helps.

Regards
Dave

 

[Phil Allison]

"David L. Jones"

Rheilly Phoull wrote:
OK, since you guys say you have the real 'gen' (not like Phil) and all
the
knowledge, how do ya calculate the values of the resistors ??
Forget all the abuse and denigration, share your superior knowledge with
me


What you do is calculate the bleeder resistor value based on the
following worst case conditions:

- The maximum voltage rating of one one of the caps

** The scenario concerns *identical, new electro* caps being used as post
inductor filters.

- Assuming one cap has maximum leakage and the other has zero leakage

** Why not assume the earth is flat while you are at it??

i.e. The capacitor with the leakage with drag the mid rail voltage away
from it's nominal half rail, creating a greater voltage across the cap
with no leakage.

** You forget the caps are in series - so any current MUST be identical
in both caps at all times !!!

You don't want to have more than the maximum capacitor
voltage across the non-leaky cap.

** I got news for you David - if an electro shows little or no leakage,
then it is well able to stand the applied voltage.

Once you assume these worse case conditions then the circuit is easy to
analyse.

** Shame all your assumptions are false.






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

 

[Uncle-Fester]

Phial Allison wrote:

"Uncle-Fester" = another anencephalic prick


** Fuck off - you rote learning moron.




.......... Phil



Sorry I cant hear you very well at all

perhaps removing roddles dick from your mouth might help you
articulate toaster boy ?

 

[Uncle-Fester]

KLR wrote:

The only way we'd have anything in common would be if I
shaved my cat's arsehole and taught it to walk backwards:
Then it would look like you!!!.


A cat's arse hole doesnt have any hair on it.

Regards
Mark


Have look did you ?

 

[Phil Allison]

"Uncle-Fester" = another anencephalic prick


** Fuck off - you rote learning moron.




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

 

[David L. Jones]

Phil Allison wrote:

"David L. Jones"

Rheilly Phoull wrote:
OK, since you guys say you have the real 'gen' (not like Phil) and all
the
knowledge, how do ya calculate the values of the resistors ??
Forget all the abuse and denigration, share your superior knowledge with
me


What you do is calculate the bleeder resistor value based on the
following worst case conditions:

- The maximum voltage rating of one one of the caps


** The scenario concerns *identical, new electro* caps being used as post
inductor filters.


- Assuming one cap has maximum leakage and the other has zero leakage


** Why not assume the earth is flat while you are at it??

It's called calculating for worst case conditions, it's a perfectly
valid way to calculate bleeder resistors.

i.e. The capacitor with the leakage with drag the mid rail voltage away
from it's nominal half rail, creating a greater voltage across the cap
with no leakage.


** You forget the caps are in series - so any current MUST be identical
in both caps at all times !!!

Not when you put bleed resistors across them! That's what we are
talking about.
If the leakage of a capacitor changes then the mid rail voltage will
change also, thus increasing the voltage across the other cap. It ain't
a simple series circuit any more when you put bleeder resistors in
PARALLEL.

You don't want to have more than the maximum capacitor
voltage across the non-leaky cap.


** I got news for you David - if an electro shows little or no leakage,
then it is well able to stand the applied voltage.


Once you assume these worse case conditions then the circuit is easy to
analyse.


** Shame all your assumptions are false.

Bleeder resistor values are always calculated using ball-park figures
and typical expected worst case conditions. In this case one cap could
be leaky and the other cap may not have any leakage, how is that a
false way to view this circuit?
The question was how to calculate bleeder resistor values for series
caps, not if they are needed or not. I gave an answer for calculating
bleeder resistor values, how would you calculate it Phil?

Dave

 

[Phil Allison]

"David L. Jones"

Phil Allison wrote:
Rheilly Phoull wrote:
OK, since you guys say you have the real 'gen' (not like Phil) and all
the
knowledge, how do ya calculate the values of the resistors ??
Forget all the abuse and denigration, share your superior knowledge
with
me


What you do is calculate the bleeder resistor value based on the
following worst case conditions:

- The maximum voltage rating of one one of the caps


** The scenario concerns *identical, new electro* caps being used as
post
inductor filters.


- Assuming one cap has maximum leakage and the other has zero leakage


** Why not assume the earth is flat while you are at it??

It's called calculating for worst case conditions,

** No electro has zero leakage and the "maximum" cannot be found except
by testing a huge number of caps.

it's a perfectly valid way to calculate bleeder resistors.

** Not with your totally mad assumptions.

i.e. The capacitor with the leakage with drag the mid rail voltage away
from it's nominal half rail, creating a greater voltage across the cap
with no leakage.


** You forget the caps are in series - so any current MUST be
identical
in both caps at all times !!!

Not when you put bleed resistors across them!

** Learn to read David, the current flowing in series connected caps must
be identical.

If the leakage of a capacitor changes then the mid rail voltage will
change also, thus increasing the voltage across the other cap. It ain't
a simple series circuit any more when you put bleeder resistors in
PARALLEL.

** Go back - you have jumped a crucial step.

You don't want to have more than the maximum capacitor
voltage across the non-leaky cap.


** I got news for you David - if an electro shows little or no leakage,
then it is well able to stand the applied voltage.


Once you assume these worse case conditions then the circuit is easy to
analyse.


** Shame all your assumptions are false.

Bleeder resistor values are always calculated using ball-park figures
and typical expected worst case conditions.

** Correct - the problem is your assumptions about these matters are
wacky.

In this case one cap could
be leaky and the other cap may not have any leakage, how is that a
false way to view this circuit?

** Zero leakage electros do not exist.

You are pulling wild assumptions out of mid air.

The question was how to calculate bleeder resistor values for series
caps, not if they are needed or not.

** The two questions are not separable.

You need realistic figures for the leakage performance and leakage v voltage
curve of the ACTUAL caps in question BEFORE any calc can be done.

I gave an answer for calculating
bleeder resistor values,

** You gave a ** bleeding stupid ** one - I doubt a *digital* person
like you has ever worked on gear with more than a 15 volt supply in your
life.

Do you claim to have any engineering experience with high voltage electros
??

how would you calculate it Phil?

** My position is that the OP does not need any in **his** app - if done
as I suggested with new, identical caps that have a 30 % or more margin of
voltage.

" ** Forget it - just use caps that have a large margin in excess of
the
needed voltage.

Eg - two 350 volt types applied to a 500 volt supply.

The caps will very soon reach a mutual, acceptable agreement on what
precise voltage suits their individual taste !! "

The reason I said this is that I have done it at least 100 times with 350
and 400 volt caps from WES and Farnell and in every case the resulting
centre voltage was within 5% of half supply.

There are OTHER situations where bleed resistors might be very worthwhile or
even essential - ie on the first stage after the rectifier where the caps
may undergo significant ripple current and hence self heating.




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

 

[David L. Jones]

Phil Allison wrote:

"David L. Jones"
Phil Allison wrote:
Rheilly Phoull wrote:
OK, since you guys say you have the real 'gen' (not like Phil) and all
the
knowledge, how do ya calculate the values of the resistors ??
Forget all the abuse and denigration, share your superior knowledge
with
me


What you do is calculate the bleeder resistor value based on the
following worst case conditions:

- The maximum voltage rating of one one of the caps


** The scenario concerns *identical, new electro* caps being used as
post
inductor filters.


- Assuming one cap has maximum leakage and the other has zero leakage


** Why not assume the earth is flat while you are at it??

It's called calculating for worst case conditions,


** No electro has zero leakage and the "maximum" cannot be found except
by testing a huge number of caps.


it's a perfectly valid way to calculate bleeder resistors.


** Not with your totally mad assumptions.


i.e. The capacitor with the leakage with drag the mid rail voltage away
from it's nominal half rail, creating a greater voltage across the cap
with no leakage.


** You forget the caps are in series - so any current MUST be
identical
in both caps at all times !!!

Not when you put bleed resistors across them!


** Learn to read David, the current flowing in series connected caps must
be identical.


If the leakage of a capacitor changes then the mid rail voltage will
change also, thus increasing the voltage across the other cap. It ain't
a simple series circuit any more when you put bleeder resistors in
PARALLEL.


** Go back - you have jumped a crucial step.


You don't want to have more than the maximum capacitor
voltage across the non-leaky cap.


** I got news for you David - if an electro shows little or no leakage,
then it is well able to stand the applied voltage.


Once you assume these worse case conditions then the circuit is easy to
analyse.


** Shame all your assumptions are false.

Bleeder resistor values are always calculated using ball-park figures
and typical expected worst case conditions.


** Correct - the problem is your assumptions about these matters are
wacky.


In this case one cap could
be leaky and the other cap may not have any leakage, how is that a
false way to view this circuit?


** Zero leakage electros do not exist.

You are pulling wild assumptions out of mid air.


The question was how to calculate bleeder resistor values for series
caps, not if they are needed or not.


** The two questions are not separable.

You need realistic figures for the leakage performance and leakage v voltage
curve of the ACTUAL caps in question BEFORE any calc can be done.



I gave an answer for calculating
bleeder resistor values,


** You gave a ** bleeding stupid ** one - I doubt a *digital* person
like you has ever worked on gear with more than a 15 volt supply in your
life.

Do you claim to have any engineering experience with high voltage electros
??


how would you calculate it Phil?


** My position is that the OP does not need any in **his** app - if done
as I suggested with new, identical caps that have a 30 % or more margin of
voltage.

" ** Forget it - just use caps that have a large margin in excess of
the
needed voltage.

Eg - two 350 volt types applied to a 500 volt supply.

The caps will very soon reach a mutual, acceptable agreement on what
precise voltage suits their individual taste !! "

The reason I said this is that I have done it at least 100 times with 350
and 400 volt caps from WES and Farnell and in every case the resulting
centre voltage was within 5% of half supply.

There are OTHER situations where bleed resistors might be very worthwhile or
even essential - ie on the first stage after the rectifier where the caps
may undergo significant ripple current and hence self heating.

Yep, that's why the question is relevant and I gave a way to calculate
the values, as asked.
How you get the "worst case" or "best case" leakage values doesn't
change the formula presented, or the way you calculate it.

You still haven't told us how you would calculate the values Phil.

Dave

 

[Phil Allison]

"David L. Jones"

( snip lots of good stuff that DLJ rudely ignored)

Yep, that's why the question is relevant and I gave a way to calculate
the values, as asked.

** The OP has a specific case in mind - but being a novice he asked an
overly general question thinking it would contain the answer he needed.

NG posters do that over and over and over - then wind up with a totally
useless answers from pedantic fuckheads like David L Jones who must
**insanely** imagine he has been presented with an some problem to solve
!!!

How you get the "worst case" or "best case" leakage values doesn't
change the formula presented, or the way you calculate it.

** So you deny posting this ?

" What you do is calculate the bleeder resistor value based on the
following worst case conditions:
- The maximum voltage rating of one one of the caps
- Assuming one cap has maximum leakage and the other has zero leakage. "


** The info you supplied is utterly useless to the OP as he has no idea what
leakage figures to use.

Apparently - since you are a digital tech using 5 volt supplies -
neither do you.

You still haven't told us how you would calculate the values Phil.

** You rudely ignored what I posted on that question:

" You need realistic figures for the leakage performance and leakage v
voltage
curve of the ACTUAL caps in question BEFORE any calc can be done. "

You also need to know all about the application and determine if the DC load
current of the bleed resistors is acceptable at all - in the OPs one,
the original caps had no bleed resistors and additional DC current would
significantly disturb supply voltage values and increase supply ripple so
that it became audible as hum.





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

 

[Phil Allison]

"Phil Allison"

**correction:

NG posters do that over and over and over - then wind up with a totally
useless answers from pedantic fuckheads like David L Jones who must
**insanely** imagine he has been presented with some *exam* problem to
solve !!!

 

[Franc Zabkar]

On Wed, 22 Jun 2005 23:10:57 +1000, Mark Harriss <billy@blartco.co.uk>
put finger to keyboard and composed:

Rheilly Phoull wrote:
G'day All
What are the rules or method to calculate the values of balancing resistors
when using electros in series ??


--
Regards ..... Rheilly Phoull




Electros have a fairly wide value tolerance and corresponding
leakage current variation, it's considered good practise to have
a resistor across each capacitor so that a series divider chain
is formed that swamps out the effect of leakage currents. If not
then the individual voltages across the caps can be imbalanced
to the point where the operating voltage of one of the electros
is exceeded: I have seen it happen and the effect does exist.

In Morgan Jones' book "Valve Amplifiers" he has a good description
of what's involved but I've loaned my copy to a friend so I can't
give an exact quote but there was some rule of thumb.

This guy has it:
http://www.jproc.ca/ve3fab/sercaps.html

Regards
Mark Harriss

Series caps are often used in dual voltage PSUs. Here is a typical
circuit with balancing resistors:
http://www.pavouk.comp.cz/hw/atxps.png


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

 

[dmm]

On Wed, 22 Jun 2005 19:39:08 +0800, "Rheilly Phoull" <Rheilly@bigpong.com> wrote:

G'day All
What are the rules or method to calculate the values of balancing resistors
when using electros in series ??

Whilst others have given their ideas as to the values (and how they are determined)
to be used, ensure that the voltage rating of the resistors exceeds the voltages
expected across the capacitors, especially for the worst possible scenario,
ie if a capacitor fails for some reason.

 

[Phil Allison]

"dmm"

Whilst others have given their ideas as to the values (and how they are
determined)
to be used, ensure that the voltage rating of the resistors exceeds the
voltages
expected across the capacitors, especially for the worst possible
scenario,
ie if a capacitor fails for some reason.

** You can't be serious ???

Worry about some 10 cent resistor failing AFTER a high voltage electro has
exploded ??

In any case, it would only do if its power ratings were exceeded.




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

 

[Uncle-Fester]

Phial Allison wrote:

"Uncle-Fester" = another anencephalic prick


** Fuck off - you rote learning moron.




.......... Phil




Sorry roddles , what's that you say ?

hard to hear over your spanking the monkey so furiously .