Re: mounting a pot core

From	Bill Sloman <bill.sloman@ieee.org>
Newsgroups	sci.electronics.design
Subject	Re: mounting a pot core
Date	2026-01-22 17:51 +1100
Organization	A noiseless patient Spider
Message-ID	<10kshda$2ovv2$1@dont-email.me> (permalink)
References	<p502nkp3a5tsrf665jlq6qqeketsdlllkq@4ax.com> <10kr3jl$29sd5$1@dont-email.me> <0o52nkd28caho2s8ier753k3j14kvg8obo@4ax.com>

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On 22/01/2026 5:18 am, john larkin wrote:
> On Thu, 22 Jan 2026 04:49:33 +1100, Bill Sloman <bill.sloman@ieee.org>
> wrote:
> 
>> On 22/01/2026 3:45 am, john larkin wrote:
>>>
>>> https://www.dropbox.com/scl/fi/d7xug1xxazoishocjcwbm/R250_Pot_Core.jpg?rlkey=sakv9lo5ov4a8lx4cjoxzn8f6&raw=1
>>>
>>> My mechanical design guy is great, and pot cores are a PITA.
>>>
>>> This will be a transmission-line transformer, and I want all the
>>> volt-seconds possible, so the pot core has to be big and barely fit in
>>> the box. I've argued that zero vertical clearance is OK - let the top
>>> cover and the PCB flex a bit - but mechanical people don't seem to
>>> like that idea.
>>
>> Pot cores aren't the only shaped bits of ferrite you can buy. RM cores
>> are another version of the same idea, and the cores that are designed to
>> be used with printed circuit windings do seem to be flatter and wider.
> 
> My intern tried several experiments of making the windings from kapton
> flex, but they weren't as fast as using coax.

The speed of electromagnet propagation is lower in Kapton that it is 
dielectrics like teflon and polyethylene, which have lower dielectric 
constants, but your Kapton flex probably wasn't designed to be a planar 
transmission line.

> A regular pot core with connectorized micro-coax wound on a bobbin is
> nice, and easy to make in production. No soldering required.
> 
>> The Siemens/TKD ferrite core catalog might be worth reading. Here's a
>> small chunk.
>>
>> https://www.tdk-electronics.tdk.com/en/529402/products/product-catalog/ferrites-and-accessories/pq-cores-and-accessories
> 
> We have samples like that. Seems to me that they would store less
> energy than a full pot core.

What matters to you is the total volume of ferrite, rather than its 
precise distribution. If you could find a wider, flatter ferrite core 
you should be able to store more energy in the same vertical headroom.

-- 
Bill Sloman, Sydney

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Thread

mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-21 08:45 -0800
  Re: mounting a pot core Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-01-21 12:28 -0500
  Re: mounting a pot core Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-01-21 12:28 -0500
    Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-21 10:11 -0800
  Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-22 04:49 +1100
    Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-21 10:18 -0800
      Re: mounting a pot core Jeroen Belleman <jeroen@nospam.please> - 2026-01-21 23:47 +0100
        Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-21 16:34 -0800
          Re: mounting a pot core Joe Gwinn <joegwinn@comcast.net> - 2026-01-21 19:48 -0500
            Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-21 17:06 -0800
            Re: mounting a pot core Jeroen Belleman <jeroen@nospam.please> - 2026-01-22 13:17 +0100
              Re: mounting a pot core Joe Gwinn <joegwinn@comcast.net> - 2026-01-22 12:47 -0500
                Re: mounting a pot core Joe Gwinn <joegwinn@comcast.net> - 2026-01-22 15:49 -0500
                Re: mounting a pot core Jeroen Belleman <jeroen@nospam.please> - 2026-01-22 23:49 +0100
          Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-22 17:57 +1100
            Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-22 08:31 -0800
              Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-23 15:57 +1100
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-23 06:24 -0800
                Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-24 03:35 +1100
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-23 08:40 -0800
                Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-24 17:01 +1100
          Re: mounting a pot core Jeroen Belleman <jeroen@nospam.please> - 2026-01-22 12:59 +0100
          Re: mounting a pot core legg <legg@nospam.magma.ca> - 2026-01-22 10:58 -0500
            Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-22 10:57 -0800
              Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-23 16:01 +1100
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-23 06:19 -0800
                Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-24 03:19 +1100
                Re: mounting a pot core liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-01-24 19:25 +0000
                Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-25 14:33 +1100
                Re: mounting a pot core liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-01-25 11:07 +0000
                Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-26 02:46 +1100
                Re: mounting a pot core legg <legg@nospam.magma.ca> - 2026-01-25 08:51 -0500
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-25 08:08 -0800
                Re: mounting a pot core legg <legg@nospam.magma.ca> - 2026-01-25 22:44 -0500
                Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-26 17:56 +1100
                Re: mounting a pot core legg <legg@nospam.magma.ca> - 2026-01-26 10:50 -0500
                Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-27 03:23 +1100
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-26 08:51 -0800
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-26 07:53 -0800
                Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-27 03:36 +1100
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-26 08:48 -0800
                Re: mounting a pot core Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-01-26 13:12 -0500
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-26 10:58 -0800
                Re: mounting a pot core Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-01-26 20:36 +0000
                Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-27 14:30 +1100
      Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-22 17:51 +1100
        Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-22 11:09 -0800
          Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-23 16:16 +1100
            Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-23 06:13 -0800
              Re: mounting a pot core Jeroen Belleman <jeroen@nospam.please> - 2026-01-23 16:07 +0100
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-23 08:22 -0800
                Re: mounting a pot core Jeroen Belleman <jeroen@nospam.please> - 2026-01-24 12:17 +0100
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-24 07:54 -0800
                Re: mounting a pot core Jeroen Belleman <jeroen@nospam.please> - 2026-01-25 13:04 +0100
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-25 07:33 -0800
                Re: mounting a pot core Jeroen Belleman <jeroen@nospam.please> - 2026-01-25 17:32 +0100
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-25 11:12 -0800
                Re: mounting a pot core JM <sunaecoNoChoppedPork@gmail.com> - 2026-01-25 19:44 +0000
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-25 13:07 -0800
                Re: mounting a pot core JM <sunaecoNoChoppedPork@gmail.com> - 2026-01-25 22:40 +0000
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-25 17:29 -0800
                Re: mounting a pot core JM <sunaecoNoChoppedPork@gmail.com> - 2026-01-25 19:40 +0000
              Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-24 03:39 +1100
                Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-23 10:09 -0800
                Re: mounting a pot core Bill Sloman <bill.sloman@ieee.org> - 2026-01-24 16:49 +1100
  Re: mounting a pot core legg <legg@nospam.magma.ca> - 2026-01-22 10:46 -0500
    Re: mounting a pot core john larkin <jl@glen--canyon.com> - 2026-01-22 11:16 -0800

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