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From: Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>
Newsgroups: sci.electronics.design
Subject: Re: Binocular choke extras
Date: Fri, 21 Mar 2025 17:33:15 -0000 (UTC)
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john larkin <jlArbor.com> wrote:
> On Thu, 20 Mar 2025 12:39:43 -0400, legg <legg@nospam.magma.ca> wrote:
> 
>> On Wed, 19 Mar 2025 23:24:36 +0100, Jeroen Belleman
>> <jeroen@nospam.please> wrote:
>> 
>>> On 3/19/25 22:40, Liz Tuddenham wrote:
>>>> I've just taken delivery of a couple of ferrite 'binocular' choke cores;
>>>> each one came with two thinwalled metal tubes and some bits of printed
>>>> circuit board.  The tubes appear to go through the holes in the choke
>>>> and the holes in the boards fit over the ends of the tubes, with copper
>>>> areas that could possibly be soldered to them.
>>>> 
>>>> Does anyone know what purpose these serve?
>>>> 
>>>> 
>>> 
>>> This sounds very much like the transformers used in wideband RF
>>> power amplifiers. See for example Helge Granberg's application
>>> note 762. The tubes with a piece of circuit board form the single-
>>> turn low impedance winding, and a number of turns of insulated
>>> copper wire going through the tubes form the high-impedance
>>> winding. This makes for a good coupling factor and consequently
>>> good wideband operation.
>>> 
>>> <https://www.communication-concepts.com/content/AN762/AN762_Application_Note.pdf>
>>> 
>>> Jeroen Belleman
>> 
>> Can also be used in directional couplers and baluns, which I suppose 
>> are just high frequency transformers by another name.
>> 
>> RL
> 
> Some people enjoy calling txline transformers "ununs" when neither end
> is a balanced load against ground.
> 
> Is there a balbal?

It’s a tree, like a baobab with pompoms


-- 
Dr Philip C D Hobbs  Principal Consultant  ElectroOptical Innovations LLC /
Hobbs ElectroOptics  Optics, Electro-optics, Photonics, Analog Electronics