S
server
Guest
On Thu, 7 Jul 2022 19:04:23 -0700 (PDT), Phil Allison
<pallison49@gmail.com> wrote:
That\'s what the caps are for!
<pallison49@gmail.com> wrote:
That\'s what the caps are for!
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Phil Allison
Guest
John Larkin wrote:
==============
** But kept secret about so you could troll everyone.
Just like you have been doing for 25 years here.
Peeeeeeuukkkeeeeee !!!!!!!!!!!
==============
No, I tested a few sample caps for another engineer, to check his
power supply Spice model and see if we\'ll have a problem with heating
from ripple current at 250 KHz. I\'m better equipped to measure these
things.
** Bet you will, polyester film caps are not rated for tolerating high frequencies with high applied voltages.
We did some testing today. One of these caps runs cold at 48 VDC and
half an amp RMS ripple curent at 250 KHz.
** So the ripple voltage is TINY !!
That\'s what the caps are for!
** But kept secret about so you could troll everyone.
Just like you have been doing for 25 years here.
Peeeeeeuukkkeeeeee !!!!!!!!!!!
S
server
Guest
On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
Surface-mount film caps would have lower inductance, but I\'ve always
found them to be unreliable. They delaminate and wash water gets
between the layers.
<pcdhSpamMeSenseless@electrooptical.net> wrote:
legg wrote:
On Thu, 7 Jul 2022 10:39:39 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:
Phil Allison wrote:
John Larkin wrote:
===============
The best one is this ugly brown radial-lead CDE thing.
https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0
The 8 nH ESL number is shocking, hard to believe,
** Did you read the maker\'s spec?
Says <1nH per mm of body and lead length.
It\'s a bog standard, Ilinois Capacitor: MMR series, metallised polyester.
https://www.farnell.com/datasheets/2900812.pdf
The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the
imperially challenged). However, that cap is 26 mm long, not even
counting the banana connectors, which ought to be above 20 nH.
I think the rule of thumb takes into account a return
path for a straight wire separated by a PCB thickness.
Nah, the 20 nH per inch number is for wire flapping in the breeze, per
the ARRL Handbook et al. It does depend slightly on the gauge.
The test jig illustrated has terminals mounted on
0.75 inch centers.
If that is being \'nulled\', then you\'d get a different
measurement, not the full loop.
The rolled film cap construction has a larger width
than a straight wire. This gives the path a reduced
L/W ration, reducing both R and L.
Yup. Also, while the field outside doesn\'t depend on the radial
distribution of current, the field inside does, and the spiral
construction forces it to be pretty well uniform.
Cheers
Phil Hobbs
Surface-mount film caps would have lower inductance, but I\'ve always
found them to be unreliable. They delaminate and wash water gets
between the layers.
A
Anthony William Sloman
Guest
On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
> On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
<snip>
So what\'s wrong with John Larkin\'s board-cleaning procedures? The industry as a whole presumably finds them reliable enough.
--
Bill Sloman, Sydney
> On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
<snip>
Surface-mount film caps would have lower inductance, but I\'ve always
found them to be unreliable. They delaminate and wash water gets
between the layers.
So what\'s wrong with John Larkin\'s board-cleaning procedures? The industry as a whole presumably finds them reliable enough.
--
Bill Sloman, Sydney
L
legg
Guest
On Thu, 7 Jul 2022 20:19:30 -0700 (PDT), Anthony William Sloman
<bill.sloman@ieee.org> wrote:
No they don\'t. They wish they could, but not so far.
SMT parts are stacked film, without any environmental seal on
the sheared edges.
They need to be sealed to survive, so conformal coatings or
encapsulation of the final assy is required.
RL
<bill.sloman@ieee.org> wrote:
On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
snip
Surface-mount film caps would have lower inductance, but I\'ve always
found them to be unreliable. They delaminate and wash water gets
between the layers.
So what\'s wrong with John Larkin\'s board-cleaning procedures? The industry as a whole presumably finds them reliable enough.
No they don\'t. They wish they could, but not so far.
SMT parts are stacked film, without any environmental seal on
the sheared edges.
They need to be sealed to survive, so conformal coatings or
encapsulation of the final assy is required.
RL
S
server
Guest
On Thu, 7 Jul 2022 19:43:52 -0700 (PDT), Phil Allison
<pallison49@gmail.com> wrote:
The post that started this thread said what I\'m doing, namely building
an LC filter in a switching regulator.
No secret there.
<pallison49@gmail.com> wrote:
John Larkin wrote:
==============
No, I tested a few sample caps for another engineer, to check his
power supply Spice model and see if we\'ll have a problem with heating
from ripple current at 250 KHz. I\'m better equipped to measure these
things.
** Bet you will, polyester film caps are not rated for tolerating high frequencies with high applied voltages.
We did some testing today. One of these caps runs cold at 48 VDC and
half an amp RMS ripple curent at 250 KHz.
** So the ripple voltage is TINY !!
That\'s what the caps are for!
** But kept secret about so you could troll everyone.
Just like you have been doing for 25 years here.
Peeeeeeuukkkeeeeee !!!!!!!!!!!
The post that started this thread said what I\'m doing, namely building
an LC filter in a switching regulator.
No secret there.
P
Phil Allison
Guest
JL is a trolling shithead
===============================
** Like hell it did.
\" We want some biggish film caps to use in some LC filters for a couple
of switching power things \"
** Reveals NOTHING.
Exactly like ALL your bullshit posts.
Wot a fake.
....... Phil
===============================
** Bet you will, polyester film caps are not rated for tolerating high frequencies with high applied voltages.
We did some testing today. One of these caps runs cold at 48 VDC and
half an amp RMS ripple curent at 250 KHz.
** So the ripple voltage is TINY !!
That\'s what the caps are for!
** But kept secret about so you could troll everyone.
Just like you have been doing for 25 years here.
Peeeeeeuukkkeeeeee !!!!!!!!!!!
The post that started this thread said what I\'m doing,
** Like hell it did.
\" We want some biggish film caps to use in some LC filters for a couple
of switching power things \"
** Reveals NOTHING.
Exactly like ALL your bullshit posts.
Wot a fake.
....... Phil
P
Phil Hobbs
Guest
jlarkin@highlandsniptechnology.com wrote:
I\'ve never used a SMT film cap on account of all the horror stories. I
recall someone here posting a Digikey product page for one, with a photo
that clearly showed delamination before it even got onto a board!
[Just checked--it was you, in a 2015 thread titled \"delaminated caps\",
but the Dropbox links are (inevitably) dead.]
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:
legg wrote:
On Thu, 7 Jul 2022 10:39:39 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:
Phil Allison wrote:
John Larkin wrote:
===============
The best one is this ugly brown radial-lead CDE thing.
https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0
The 8 nH ESL number is shocking, hard to believe,
** Did you read the maker\'s spec?
Says <1nH per mm of body and lead length.
It\'s a bog standard, Ilinois Capacitor: MMR series, metallised polyester.
https://www.farnell.com/datasheets/2900812.pdf
The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the
imperially challenged). However, that cap is 26 mm long, not even
counting the banana connectors, which ought to be above 20 nH.
I think the rule of thumb takes into account a return
path for a straight wire separated by a PCB thickness.
Nah, the 20 nH per inch number is for wire flapping in the breeze, per
the ARRL Handbook et al. It does depend slightly on the gauge.
The test jig illustrated has terminals mounted on
0.75 inch centers.
If that is being \'nulled\', then you\'d get a different
measurement, not the full loop.
The rolled film cap construction has a larger width
than a straight wire. This gives the path a reduced
L/W ration, reducing both R and L.
Yup. Also, while the field outside doesn\'t depend on the radial
distribution of current, the field inside does, and the spiral
construction forces it to be pretty well uniform.
Cheers
Phil Hobbs
Surface-mount film caps would have lower inductance, but I\'ve always
found them to be unreliable. They delaminate and wash water gets
between the layers.
I\'ve never used a SMT film cap on account of all the horror stories. I
recall someone here posting a Digikey product page for one, with a photo
that clearly showed delamination before it even got onto a board!
[Just checked--it was you, in a 2015 thread titled \"delaminated caps\",
but the Dropbox links are (inevitably) dead.]
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
S
server
Guest
On Thu, 7 Jul 2022 23:19:07 -0700 (PDT), Phil Allison
<pallison49@gmail.com> wrote:
The problem was pretty clear. If the issue interested you, and you
didn\'t understand what I\'m doing, you could have asked.
The filter is actually interesting. We have a 60-volt 250 KHz 2-fet
half-bridge and it needs to be lowpass filtered to make a clean 0 to
36 volt programmable DC power supply. We\'ll digitize the final output
voltage and current and close the loops in an FPGA, which then makes
the PWM into the fets. So the filter needs to really kill the 250 KHz
ripple (without frying itself) but have low phase shift and low Q so
it doesn\'t wreck the control loop. And it has to be made out of parts
that we have or can actually buy now.
Turns out that, among other things, the Rds-on of the fets is an
important part of the filter response.
We sim\'d this with the LTC4444 gate drivers but prefer to use the TI
UCC27712. We just tested that and it\'s excellent. Ignoring the data
sheet, we just connect directly to the fet gates.
Here\'s my little half-bridge test board, before massive hacks:
https://www.dropbox.com/s/2x8z6yn29ab57xf/Z524_Wing_1.jpg?raw=1
It\'s regulating 200 watts and barely getting warm.
<pallison49@gmail.com> wrote:
JL is a trolling shithead
===============================
** Bet you will, polyester film caps are not rated for tolerating high frequencies with high applied voltages.
We did some testing today. One of these caps runs cold at 48 VDC and
half an amp RMS ripple curent at 250 KHz.
** So the ripple voltage is TINY !!
That\'s what the caps are for!
** But kept secret about so you could troll everyone.
Just like you have been doing for 25 years here.
Peeeeeeuukkkeeeeee !!!!!!!!!!!
The post that started this thread said what I\'m doing,
** Like hell it did.
\" We want some biggish film caps to use in some LC filters for a couple
of switching power things \"
** Reveals NOTHING.
Exactly like ALL your bullshit posts.
Wot a fake.
...... Phil
The problem was pretty clear. If the issue interested you, and you
didn\'t understand what I\'m doing, you could have asked.
The filter is actually interesting. We have a 60-volt 250 KHz 2-fet
half-bridge and it needs to be lowpass filtered to make a clean 0 to
36 volt programmable DC power supply. We\'ll digitize the final output
voltage and current and close the loops in an FPGA, which then makes
the PWM into the fets. So the filter needs to really kill the 250 KHz
ripple (without frying itself) but have low phase shift and low Q so
it doesn\'t wreck the control loop. And it has to be made out of parts
that we have or can actually buy now.
Turns out that, among other things, the Rds-on of the fets is an
important part of the filter response.
We sim\'d this with the LTC4444 gate drivers but prefer to use the TI
UCC27712. We just tested that and it\'s excellent. Ignoring the data
sheet, we just connect directly to the fet gates.
Here\'s my little half-bridge test board, before massive hacks:
https://www.dropbox.com/s/2x8z6yn29ab57xf/Z524_Wing_1.jpg?raw=1
It\'s regulating 200 watts and barely getting warm.
S
server
Guest
On Fri, 8 Jul 2022 09:40:56 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
I don\'t know why people still sell these horrors. I\'ve never seen one
on a piece of production gear.
<pcdhSpamMeSenseless@electrooptical.net> wrote:
jlarkin@highlandsniptechnology.com wrote:
On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:
legg wrote:
On Thu, 7 Jul 2022 10:39:39 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:
Phil Allison wrote:
John Larkin wrote:
===============
The best one is this ugly brown radial-lead CDE thing.
https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0
The 8 nH ESL number is shocking, hard to believe,
** Did you read the maker\'s spec?
Says <1nH per mm of body and lead length.
It\'s a bog standard, Ilinois Capacitor: MMR series, metallised polyester.
https://www.farnell.com/datasheets/2900812.pdf
The usual rule-of-thumb for wire is 20 nH per inch (800 pH/mm for the
imperially challenged). However, that cap is 26 mm long, not even
counting the banana connectors, which ought to be above 20 nH.
I think the rule of thumb takes into account a return
path for a straight wire separated by a PCB thickness.
Nah, the 20 nH per inch number is for wire flapping in the breeze, per
the ARRL Handbook et al. It does depend slightly on the gauge.
The test jig illustrated has terminals mounted on
0.75 inch centers.
If that is being \'nulled\', then you\'d get a different
measurement, not the full loop.
The rolled film cap construction has a larger width
than a straight wire. This gives the path a reduced
L/W ration, reducing both R and L.
Yup. Also, while the field outside doesn\'t depend on the radial
distribution of current, the field inside does, and the spiral
construction forces it to be pretty well uniform.
Cheers
Phil Hobbs
Surface-mount film caps would have lower inductance, but I\'ve always
found them to be unreliable. They delaminate and wash water gets
between the layers.
I\'ve never used a SMT film cap on account of all the horror stories. I
recall someone here posting a Digikey product page for one, with a photo
that clearly showed delamination before it even got onto a board!
[Just checked--it was you, in a 2015 thread titled \"delaminated caps\",
but the Dropbox links are (inevitably) dead.]
Cheers
Phil Hobbs
I don\'t know why people still sell these horrors. I\'ve never seen one
on a piece of production gear.
J
John Larkin
Guest
On Wed, 06 Jul 2022 14:34:59 -0700, John Larkin
<jlarkin@highland_atwork_technology.com> wrote:
Here\'s a test of the c-v of a ceramic cap. We\'ll run at 60 volts as a
supply bypass, so we\'ll get about 1.2 uF, which will be OK if we put a
few in parallel with one big electro. That\'s smaller and less ESL than
a giant film cap.
https://www.dropbox.com/sh/7zlc8v29tgyoxrx/AABIyneKVEV-xX330TZTi4qTa?dl=0
We still need the big films in the supply output filter.
--
If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon
<jlarkin@highland_atwork_technology.com> wrote:
We want some biggish film caps to use in some LC filters for a couple
of switching power things, so we got some to test.
The best one is this ugly brown radial-lead CDE thing.
https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0
The 8 nH ESL number is shocking, hard to believe, but if I scrooch it
into the test rig with longer leads the ESL spikes go way up,
consistent with the loop area, so the low ESL seems real. It will be
even lower soldered on a PCB, into some hunky copper planes.
Of course ESL is not a lumped property of a wound film cap, but this
is close.
We were considering some big ceramic caps, but they lose 80% of their
c at our 48 volts DC.
Here\'s a test of the c-v of a ceramic cap. We\'ll run at 60 volts as a
supply bypass, so we\'ll get about 1.2 uF, which will be OK if we put a
few in parallel with one big electro. That\'s smaller and less ESL than
a giant film cap.
https://www.dropbox.com/sh/7zlc8v29tgyoxrx/AABIyneKVEV-xX330TZTi4qTa?dl=0
We still need the big films in the supply output filter.
--
If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon
E
ehsjr
Guest
On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
predujice showing through. It\'s time someone pointed it out
to you.
> The industry as a whole presumably finds them reliable enough.
Nothing. This is just another example of your anti-LarkinOn Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
snip
Surface-mount film caps would have lower inductance, but I\'ve always
found them to be unreliable. They delaminate and wash water gets
between the layers.
So what\'s wrong with John Larkin\'s board-cleaning procedures?
predujice showing through. It\'s time someone pointed it out
to you.
> The industry as a whole presumably finds them reliable enough.
P
Phil Hobbs
Guest
John Larkin wrote:
Ceramic caps\' C(V) curves are all over the map. The
drudgery required to find a part that \'achieves\' 70% of its rated
capacitance at *gasp* 30% of its rated voltage has got old, old, old,
old, and old. (Did I mention old?)
At this point, when we find a reasonably acceptable one, we hold our
noses and do a lifetime buy.
On the plus side, the good manufacturers have websites where you can get
reasonably accurate C(V) curves, but the amount of assing around is
assssstrononmical.
Cheerssss
Phil Hobbsssss
On Wed, 06 Jul 2022 14:34:59 -0700, John Larkin
jlarkin@highland_atwork_technology.com> wrote:
We want some biggish film caps to use in some LC filters for a couple
of switching power things, so we got some to test.
The best one is this ugly brown radial-lead CDE thing.
https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0
The 8 nH ESL number is shocking, hard to believe, but if I scrooch it
into the test rig with longer leads the ESL spikes go way up,
consistent with the loop area, so the low ESL seems real. It will be
even lower soldered on a PCB, into some hunky copper planes.
Of course ESL is not a lumped property of a wound film cap, but this
is close.
We were considering some big ceramic caps, but they lose 80% of their
c at our 48 volts DC.
Here\'s a test of the c-v of a ceramic cap. We\'ll run at 60 volts as a
supply bypass, so we\'ll get about 1.2 uF, which will be OK if we put a
few in parallel with one big electro. That\'s smaller and less ESL than
a giant film cap.
https://www.dropbox.com/sh/7zlc8v29tgyoxrx/AABIyneKVEV-xX330TZTi4qTa?dl=0
We still need the big films in the supply output filter.
Ceramic caps\' C(V) curves are all over the map. The
drudgery required to find a part that \'achieves\' 70% of its rated
capacitance at *gasp* 30% of its rated voltage has got old, old, old,
old, and old. (Did I mention old?)
At this point, when we find a reasonably acceptable one, we hold our
noses and do a lifetime buy.
On the plus side, the good manufacturers have websites where you can get
reasonably accurate C(V) curves, but the amount of assing around is
assssstrononmical.
Cheerssss
Phil Hobbsssss
A
Anthony William Sloman
Guest
On Saturday, July 9, 2022 at 8:23:23 AM UTC+10, ehsjr wrote:
It was a perfectly sensible question. And it has got a perfectly sensible answer
> > The industry as a whole presumably finds them reliable enough.
As legg pointed out
So it wasn\'t John Larkin\'s board cleaning procedures that were inadequate, but rather his failure to apply a conformal coating to what he clearly now knows to be a vulnerable part.
I ended up getting educated because I posted a sensible question. If you want to see a posting sensible questions that gets a sensible answer as an \"exhibition of anti-Larkin prejudice\" you\'ve got your own kind of problem, and it might be that time someone pointed it out to you.
--
Bill Sloman, Sydney
On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
snip
Surface-mount film caps would have lower inductance, but I\'ve always
found them to be unreliable. They delaminate and wash water gets
between the layers.
So what\'s wrong with John Larkin\'s board-cleaning procedures?
Nothing. This is just another example of your anti-Larkin prejudice showing through. It\'s time someone pointed it out to you.
It was a perfectly sensible question. And it has got a perfectly sensible answer
> > The industry as a whole presumably finds them reliable enough.
As legg pointed out
No they don\'t. They wish they could, but not so far.
SMT parts are stacked film, without any environmental seal on the sheared edges.
They need to be sealed to survive, so conformal coatings encapsulation of the final assy is required.
So it wasn\'t John Larkin\'s board cleaning procedures that were inadequate, but rather his failure to apply a conformal coating to what he clearly now knows to be a vulnerable part.
I ended up getting educated because I posted a sensible question. If you want to see a posting sensible questions that gets a sensible answer as an \"exhibition of anti-Larkin prejudice\" you\'ve got your own kind of problem, and it might be that time someone pointed it out to you.
--
Bill Sloman, Sydney
J
John Larkin
Guest
On Fri, 8 Jul 2022 18:23:14 -0400, ehsjr <ehsjr@verizon.net> wrote:
He reflexively declares me to be wrong about everything, because his
emotions totally dominate his ability to reason. Or to use google.
Ignore him.
--
If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon
On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
snip
Surface-mount film caps would have lower inductance, but I\'ve always
found them to be unreliable. They delaminate and wash water gets
between the layers.
So what\'s wrong with John Larkin\'s board-cleaning procedures?
Nothing. This is just another example of your anti-Larkin
predujice showing through. It\'s time someone pointed it out
to you.
The industry as a whole presumably finds them reliable enough.
He reflexively declares me to be wrong about everything, because his
emotions totally dominate his ability to reason. Or to use google.
Ignore him.
--
If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon
A
Anthony William Sloman
Guest
On Saturday, July 9, 2022 at 11:19:21 AM UTC+10, John Larkin wrote:
Legg pointed out that you should have used a conformable coating on your stacked film capacitors if you were going to put them through a water wash.
The reasonable point I was making was that you must have got something wrong if you found them to be unreliable. I don\'t make \"reflexive declarations\" and I certainly don\'t claim that you are wrong about everything - though your ideas about anthropogenic global warming are remarkably consistently wrong.
> Ignore him.
Blanket advice, of the kind you were objecting to. If you bothered to read what I actually post, you might produce less reflexive responses, but since what you seem to be looking for is uncritical flattery you are probably right to skip my comments.
--
Bill Sloman, Sydney
On Fri, 8 Jul 2022 18:23:14 -0400, ehsjr <eh...@verizon.net> wrote:
On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
snip
Surface-mount film caps would have lower inductance, but I\'ve always
found them to be unreliable. They delaminate and wash water gets
between the layers.
So what\'s wrong with John Larkin\'s board-cleaning procedures?
The industry as a whole presumably finds them reliable enough.
Nothing. This is just another example of your anti-Larkin
prejudice showing through. It\'s time someone pointed it out
to you.
He reflexively declares me to be wrong about everything, because his emotions totally dominate his ability to reason. Or to use google.
Legg pointed out that you should have used a conformable coating on your stacked film capacitors if you were going to put them through a water wash.
The reasonable point I was making was that you must have got something wrong if you found them to be unreliable. I don\'t make \"reflexive declarations\" and I certainly don\'t claim that you are wrong about everything - though your ideas about anthropogenic global warming are remarkably consistently wrong.
> Ignore him.
Blanket advice, of the kind you were objecting to. If you bothered to read what I actually post, you might produce less reflexive responses, but since what you seem to be looking for is uncritical flattery you are probably right to skip my comments.
--
Bill Sloman, Sydney
W
whit3rd
Guest
On Friday, July 8, 2022 at 5:01:07 PM UTC-7, bill....@ieee.org wrote:
That seems odd; you don\'t want to conformal coat before soldering, and you don\'t want to
solder, then conformal coat before washing, do you?
I suppose you could install wire-wrap posts, clean the board, but conformal coat (the capacitors), then
rely on wire-wrap attachment of the capacitors to insulation-displace the coating...
otherwise, the conformal coating that matters has to be selectively applied
before putting the parts into a reel. One hopes
the capacitor manufacture process has been designed with this issue in mind.
On Saturday, July 9, 2022 at 8:23:23 AM UTC+10, ehsjr wrote:
On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
Surface-mount film caps would have lower inductance, but I\'ve always
found them to be unreliable. They delaminate and wash water gets
between the layers.
So what\'s wrong with John Larkin\'s board-cleaning procedures?
Nothing. This is just another example of your anti-Larkin prejudice showing through. It\'s time someone pointed it out to you.
It was a perfectly sensible question. And it has got a perfectly sensible answer
The industry as a whole presumably finds them reliable enough.
As legg pointed out
No they don\'t. They wish they could, but not so far.
SMT parts are stacked film, without any environmental seal on the sheared edges.
They need to be sealed to survive, so conformal coatings encapsulation of the final assy is required.
So it wasn\'t John Larkin\'s board cleaning procedures that were inadequate, but rather his failure to apply a conformal coating to what he clearly now knows to be a vulnerable part.
That seems odd; you don\'t want to conformal coat before soldering, and you don\'t want to
solder, then conformal coat before washing, do you?
I suppose you could install wire-wrap posts, clean the board, but conformal coat (the capacitors), then
rely on wire-wrap attachment of the capacitors to insulation-displace the coating...
otherwise, the conformal coating that matters has to be selectively applied
before putting the parts into a reel. One hopes
the capacitor manufacture process has been designed with this issue in mind.
S
server
Guest
On Fri, 8 Jul 2022 22:25:22 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:
Sounds labor intensive.
Just use radial leaded film caps.
When I wanted to see the innards of my brown 6.8u film cap. I put it
on an anvil and hit it with a hammer. Nothing happened. The way to get
inside was to put it in a big vise, lengthwise, and squeeze it until
the shell shattered.
wrote:
On Friday, July 8, 2022 at 5:01:07 PM UTC-7, bill....@ieee.org wrote:
On Saturday, July 9, 2022 at 8:23:23 AM UTC+10, ehsjr wrote:
On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
Surface-mount film caps would have lower inductance, but I\'ve always
found them to be unreliable. They delaminate and wash water gets
between the layers.
So what\'s wrong with John Larkin\'s board-cleaning procedures?
Nothing. This is just another example of your anti-Larkin prejudice showing through. It\'s time someone pointed it out to you.
It was a perfectly sensible question. And it has got a perfectly sensible answer
The industry as a whole presumably finds them reliable enough.
As legg pointed out
No they don\'t. They wish they could, but not so far.
SMT parts are stacked film, without any environmental seal on the sheared edges.
They need to be sealed to survive, so conformal coatings encapsulation of the final assy is required.
So it wasn\'t John Larkin\'s board cleaning procedures that were inadequate, but rather his failure to apply a conformal coating to what he clearly now knows to be a vulnerable part.
That seems odd; you don\'t want to conformal coat before soldering, and you don\'t want to
solder, then conformal coat before washing, do you?
I suppose you could install wire-wrap posts, clean the board, but conformal coat (the capacitors), then
rely on wire-wrap attachment of the capacitors to insulation-displace the coating...
otherwise, the conformal coating that matters has to be selectively applied
before putting the parts into a reel.
Sounds labor intensive.
One hopes
the capacitor manufacture process has been designed with this issue in mind.
Just use radial leaded film caps.
When I wanted to see the innards of my brown 6.8u film cap. I put it
on an anvil and hit it with a hammer. Nothing happened. The way to get
inside was to put it in a big vise, lengthwise, and squeeze it until
the shell shattered.
S
server
Guest
On Fri, 8 Jul 2022 18:23:48 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
There seems to be an unofficial concensus that hi-K ceramic caps are
are rated for the voltage that makes 10% of their rated capacitance.
They can generally stand several times that voltage.
<pcdhSpamMeSenseless@electrooptical.net> wrote:
John Larkin wrote:
On Wed, 06 Jul 2022 14:34:59 -0700, John Larkin
jlarkin@highland_atwork_technology.com> wrote:
We want some biggish film caps to use in some LC filters for a couple
of switching power things, so we got some to test.
The best one is this ugly brown radial-lead CDE thing.
https://www.dropbox.com/sh/d2mwz6i6yr0j9sp/AACJZ9IfJEGzdk0WGwsFb0MCa?dl=0
The 8 nH ESL number is shocking, hard to believe, but if I scrooch it
into the test rig with longer leads the ESL spikes go way up,
consistent with the loop area, so the low ESL seems real. It will be
even lower soldered on a PCB, into some hunky copper planes.
Of course ESL is not a lumped property of a wound film cap, but this
is close.
We were considering some big ceramic caps, but they lose 80% of their
c at our 48 volts DC.
Here\'s a test of the c-v of a ceramic cap. We\'ll run at 60 volts as a
supply bypass, so we\'ll get about 1.2 uF, which will be OK if we put a
few in parallel with one big electro. That\'s smaller and less ESL than
a giant film cap.
https://www.dropbox.com/sh/7zlc8v29tgyoxrx/AABIyneKVEV-xX330TZTi4qTa?dl=0
We still need the big films in the supply output filter.
Ceramic caps\' C(V) curves are all over the map. The
drudgery required to find a part that \'achieves\' 70% of its rated
capacitance at *gasp* 30% of its rated voltage has got old, old, old,
old, and old. (Did I mention old?)
At this point, when we find a reasonably acceptable one, we hold our
noses and do a lifetime buy.
On the plus side, the good manufacturers have websites where you can get
reasonably accurate C(V) curves, but the amount of assing around is
assssstrononmical.
Cheerssss
Phil Hobbsssss
There seems to be an unofficial concensus that hi-K ceramic caps are
are rated for the voltage that makes 10% of their rated capacitance.
They can generally stand several times that voltage.
P
Phil Hobbs
Guest
jlarkin@highlandsniptechnology.com wrote:
Yeah, through-hole film caps rock. They\'re really the only technology
for applications needing good linearity at higher CV values than you can
get in C0G. One typical use for us is filtering the bias supplies for
avalanche photodiodes and SiPMs, but they\'re also good for slow analog
ramps.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com
On Fri, 8 Jul 2022 22:25:22 -0700 (PDT), whit3rd <whit3rd@gmail.com
wrote:
On Friday, July 8, 2022 at 5:01:07 PM UTC-7, bill....@ieee.org wrote:
On Saturday, July 9, 2022 at 8:23:23 AM UTC+10, ehsjr wrote:
On 7/7/2022 11:19 PM, Anthony William Sloman wrote:
On Friday, July 8, 2022 at 12:46:22 PM UTC+10, jla...@highlandsniptechnology.com wrote:
On Thu, 7 Jul 2022 18:27:24 -0400, Phil Hobbs <pcdhSpamM...@electrooptical.net> wrote:
Surface-mount film caps would have lower inductance, but I\'ve always
found them to be unreliable. They delaminate and wash water gets
between the layers.
So what\'s wrong with John Larkin\'s board-cleaning procedures?
Nothing. This is just another example of your anti-Larkin prejudice showing through. It\'s time someone pointed it out to you.
It was a perfectly sensible question. And it has got a perfectly sensible answer
The industry as a whole presumably finds them reliable enough.
As legg pointed out
No they don\'t. They wish they could, but not so far.
SMT parts are stacked film, without any environmental seal on the sheared edges.
They need to be sealed to survive, so conformal coatings encapsulation of the final assy is required.
So it wasn\'t John Larkin\'s board cleaning procedures that were inadequate, but rather his failure to apply a conformal coating to what he clearly now knows to be a vulnerable part.
That seems odd; you don\'t want to conformal coat before soldering, and you don\'t want to
solder, then conformal coat before washing, do you?
I suppose you could install wire-wrap posts, clean the board, but conformal coat (the capacitors), then
rely on wire-wrap attachment of the capacitors to insulation-displace the coating...
otherwise, the conformal coating that matters has to be selectively applied
before putting the parts into a reel.
Sounds labor intensive.
One hopes
the capacitor manufacture process has been designed with this issue in mind.
Just use radial leaded film caps.
When I wanted to see the innards of my brown 6.8u film cap. I put it
on an anvil and hit it with a hammer. Nothing happened. The way to get
inside was to put it in a big vise, lengthwise, and squeeze it until
the shell shattered.
Yeah, through-hole film caps rock. They\'re really the only technology
for applications needing good linearity at higher CV values than you can
get in C0G. One typical use for us is filtering the bias supplies for
avalanche photodiodes and SiPMs, but they\'re also good for slow analog
ramps.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com