https://www.mouser.com/ProductDetail/KEMET/CKC33C224KDGLCTU?qs=sGAEpiMZZMvsSlwiRhF8qtsGU%2FCnaNeQZfloC%2Fa%2FQTldKZA3leWJsw%3D%3D

$27 each. I think I'll use film.

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john larkin <jl@glen--canyon.com> wrote:

https://www.mouser.com/ProductDetail/KEMET/CKC33C224KDGLCTU?qs=sGAEpiMZZMvsSlwiRhF8qtsGU%2FCnaNeQZfloC%2Fa%2FQTldKZA3leWJsw%3D%3D

$27 each. I think I'll use film.

Nothing strange, just a relatively big stacked HIGH VOLTAGE and [relatively] HIGH CAPACITANCE (at least for such voltage rating) _C0G_ ceramic capacitor. The interesting thing is that it is sintered into a relatively small almost monolithic block that can be installed two ways. Earlier such stacked capacitors were made by soldering several separate caps to flat bus bar like leads with a high temperature solder. That was adding inductance and didn't allow the "Low Loss" mounting as it is shown in the datasheet for this one. They also were mostly thruhole parts, with several pins on those bus bar
leads for soldering into TH pads.

No wonder it is THAT expensive -- it is not a jellybean part that cost a
dollar per bucket and you put them all over left and right...

A comparable film capacitor will be bigger and will have significantly
poorer ESL and ESR.

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On 10/07/2025 11:52 am, Sergey Kubushyn wrote:

john larkin <jl@glen--canyon.com> wrote:

https://www.mouser.com/ProductDetail/KEMET/CKC33C224KDGLCTU?qs=sGAEpiMZZMvsSlwiRhF8qtsGU%2FCnaNeQZfloC%2Fa%2FQTldKZA3leWJsw%3D%3D

$27 each. I think I'll use film.

Nothing strange, just a relatively big stacked HIGH VOLTAGE and [relatively] HIGH CAPACITANCE (at least for such voltage rating) _C0G_ ceramic capacitor. The interesting thing is that it is sintered into a relatively small almost monolithic block that can be installed two ways. Earlier such stacked capacitors were made by soldering several separate caps to flat bus bar like leads with a high temperature solder. That was adding inductance and didn't allow the "Low Loss" mounting as it is shown in the datasheet for this one. They also were mostly thruhole parts, with several pins on those bus bar leads for soldering into TH pads.

No wonder it is THAT expensive -- it is not a jellybean part that cost a dollar per bucket and you put them all over left and right...

A comparable film capacitor will be bigger and will have significantly
poorer ESL and ESR.

The data sheet doesn't say much about ESL and ESR - maximum values are
listed on page five of the data sheet. They are clearly low, and the
data sheet does spell out how the devices are structured to keep them low.

John Larkin doesn't seem to like getting his head around this kind of
pesky detail.

--
Bill Sloman, Sydney

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On Thu, 10 Jul 2025 01:52:42 -0000 (UTC), Sergey Kubushyn
<ksi@koi8.net> wrote:

john larkin <jl@glen--canyon.com> wrote:

https://www.mouser.com/ProductDetail/KEMET/CKC33C224KDGLCTU?qs=sGAEpiMZZMvsSlwiRhF8qtsGU%2FCnaNeQZfloC%2Fa%2FQTldKZA3leWJsw%3D%3D

$27 each. I think I'll use film.

Nothing strange, just a relatively big stacked HIGH VOLTAGE and [relatively] >HIGH CAPACITANCE (at least for such voltage rating) _C0G_ ceramic capacitor. >The interesting thing is that it is sintered into a relatively small almost >monolithic block that can be installed two ways. Earlier such stacked >capacitors were made by soldering several separate caps to flat bus bar like >leads with a high temperature solder. That was adding inductance and didn't >allow the "Low Loss" mounting as it is shown in the datasheet for this one. >They also were mostly thruhole parts, with several pins on those bus bar >leads for soldering into TH pads.

No wonder it is THAT expensive -- it is not a jellybean part that cost a >dollar per bucket and you put them all over left and right...

A comparable film capacitor will be bigger and will have significantly
poorer ESL and ESR.

ESL for sure. Ceramics and self-healing films can have considerable
ESR too.

Of course I'd parallel a couple big leaded film caps with a few
surface-mount ceramics.

I can get 1 uF at 1KV in a film cap for well under $2.

This is for a 750 volt into 50-ohm pulser with, optimistically, under
1 ns edges.

We could even use polymer electrolytics in series to get the voltage.
We'd get lots of C. ESR and ESL are impressive on polymers.

https://www.dropbox.com/scl/fi/bvx38d23enwxx20tv7rgw/Kemet_A765EB187M0JLAE020_TDR.jpg?rlkey=7ieq6ughiij6twxreej7ooeq9&raw=1

https://www.dropbox.com/scl/fi/215r24f5wfjcrupr2d32w/KEMET_A765EB187M0JLAE020_ESR_100mA_.png?rlkey=g03gvzne50ov1f01fhiyleccp&raw=1

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On 7/10/25 11:00, john larkin wrote:

On Thu, 10 Jul 2025 01:52:42 -0000 (UTC), Sergey Kubushyn
<ksi@koi8.net> wrote:

john larkin <jl@glen--canyon.com> wrote:

https://www.mouser.com/ProductDetail/KEMET/CKC33C224KDGLCTU?qs=sGAEpiMZZMvsSlwiRhF8qtsGU%2FCnaNeQZfloC%2Fa%2FQTldKZA3leWJsw%3D%3D

$27 each. I think I'll use film.

Nothing strange, just a relatively big stacked HIGH VOLTAGE and [relatively] >> HIGH CAPACITANCE (at least for such voltage rating) _C0G_ ceramic capacitor. >> The interesting thing is that it is sintered into a relatively small almost >> monolithic block that can be installed two ways. Earlier such stacked
capacitors were made by soldering several separate caps to flat bus bar like >> leads with a high temperature solder. That was adding inductance and didn't >> allow the "Low Loss" mounting as it is shown in the datasheet for this one. >> They also were mostly thruhole parts, with several pins on those bus bar
leads for soldering into TH pads.

No wonder it is THAT expensive -- it is not a jellybean part that cost a
dollar per bucket and you put them all over left and right...

A comparable film capacitor will be bigger and will have significantly
poorer ESL and ESR.

ESL for sure. Ceramics and self-healing films can have considerable
ESR too.

Of course I'd parallel a couple big leaded film caps with a few
surface-mount ceramics.

I can get 1 uF at 1KV in a film cap for well under $2.

This is for a 750 volt into 50-ohm pulser with, optimistically, under
1 ns edges.

We could even use polymer electrolytics in series to get the voltage.
We'd get lots of C. ESR and ESL are impressive on polymers.

https://www.dropbox.com/scl/fi/bvx38d23enwxx20tv7rgw/Kemet_A765EB187M0JLAE020_TDR.jpg?rlkey=7ieq6ughiij6twxreej7ooeq9&raw=1

https://www.dropbox.com/scl/fi/215r24f5wfjcrupr2d32w/KEMET_A765EB187M0JLAE020_ESR_100mA_.png?rlkey=g03gvzne50ov1f01fhiyleccp&raw=1

The ESL of a rolled film cap can be extraordinarily small, actually,
like 8 nH for an inch-long specimen. That's less than half that of an
inch of hookup wire (~20 nH), on account of the large outer diameter.
It depends on the construction, I expect--if it has solid ends that
directly connect with all metal layers, it just looks like a solid bar magnetically.

Stacked film is similar.

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

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On Wed, 09 Jul 2025 16:01:31 -0700, john larkin <jl@glen--canyon.com>
wrote:

https://www.mouser.com/ProductDetail/KEMET/CKC33C224KDGLCTU?qs=sGAEpiMZZMvsSlwiRhF8qtsGU%2FCnaNeQZfloC%2Fa%2FQTldKZA3leWJsw%3D%3D

$27 each. I think I'll use film.

Difference in ratings between standard and 'low loss' configuration
seems to be even thermal coupling between components and the board -
resulting in higher current rating for the same temperature rise.

This allows higher loss from the same basic package.

So not really 'low loss'.

There are performance issues for stacked film parts that address
the same issue, for lower temperature limits.

Not something that through-hole packages can easily address.

RL

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