Groups > sci.electronics.design > #433623

Re: 50 ohms to 0.02 ohm transformer

From	Jeroen Belleman <jeroen@nospam.please>
Newsgroups	sci.electronics.design
Subject	Re: 50 ohms to 0.02 ohm transformer
Date	2016-11-03 14:58 +0100
Organization	Aioe.org NNTP Server
Message-ID	<nvffqd$sjv$1@gioia.aioe.org> (permalink)
References	<nvfc2s$6r6$1@dont-email.me>

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On 2016-11-03 13:55, amdx wrote:
> I want to build a 50 ohm to 0.02 ohm transformer.
> It needs a 50 to 1 turns ratio.
>   It takes a low A sub L core to make such a thing.
> I have a toroid with an A sub L of 75. That only needs
> 29 turns for my frequency of interest 500KHz to 1700kHz.
> I also have some potcores that I could gap to lower the A sub L.
>
> What would make a better transformer a toroid or a gapped potcore?
>
>   I plan 50 turns with a 1 turn secondary.
>
> What problems can I expect with a 1 turn secondary?
>
>                          Thanks,     Mikek

A bandwidth ratio of only three should be dead-easy,
but the 20 mOhm impedance may spell trouble.
The single-turn winding should be fat and compact.
A single nH of stray inductance (!) or ten mOhms
of resistance would ruin performance. I think I would
implement it as several single-turn windings in parallel,
distributed around a toroid. What will you connect
to the 20mOhm side?

Why would you need low A_l? The usual rule of having the
reactance of one winding four times the terminal impedance
is only a minimum. There is no harm in going higher. There
would be if you did it by using more turns though.

Use a toroid. Gapped cores are for energy storage,
not for transformers.

Jeroen Belleman

Thread

50 ohms to 0.02 ohm transformer amdx <nojunk@knology.net> - 2016-11-03 07:55 -0500
  Re: 50 ohms to 0.02 ohm transformer Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2016-11-03 15:12 +0200
    Re: 50 ohms to 0.02 ohm transformer John Larkin <jjlarkin@highlandtechnology.com> - 2016-11-03 10:55 -0700
      Re: 50 ohms to 0.02 ohm transformer amdx <nojunk@knology.net> - 2016-11-03 16:56 -0500
        Re: 50 ohms to 0.02 ohm transformer amdx <nojunk@knology.net> - 2016-11-03 20:36 -0500
        Re: 50 ohms to 0.02 ohm transformer Syd Rumpo <usenet@nononono.co.uk> - 2016-11-08 23:35 +0000
        Re: 50 ohms to 0.02 ohm transformer Lasse Langwadt Christensen <langwadt@fonz.dk> - 2016-11-08 15:51 -0800
          Re: 50 ohms to 0.02 ohm transformer amdx <nojunk@knology.net> - 2016-11-08 21:45 -0600
          Re: 50 ohms to 0.02 ohm transformer Jasen Betts <jasen@xnet.co.nz> - 2016-11-10 03:28 +0000
      Re: 50 ohms to 0.02 ohm transformer Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2016-11-04 10:41 +0200
        Re: 50 ohms to 0.02 ohm transformer Jeroen Belleman <jeroen@nospam.please> - 2016-11-04 10:54 +0100
      Re: 50 ohms to 0.02 ohm transformer bill.sloman@ieee.org - 2016-11-04 06:00 -0700
        Re: 50 ohms to 0.02 ohm transformer Jeroen Belleman <jeroen@nospam.please> - 2016-11-04 14:10 +0100
          Re: 50 ohms to 0.02 ohm transformer John Larkin <jjlarkin@highlandtechnology.com> - 2016-11-04 08:08 -0700
      Re: 50 ohms to 0.02 ohm transformer "Tim Williams" <tiwill@seventransistorlabs.com> - 2016-11-04 22:13 -0500
  Re: 50 ohms to 0.02 ohm transformer Jeroen Belleman <jeroen@nospam.please> - 2016-11-03 14:58 +0100
    Re: 50 ohms to 0.02 ohm transformer amdx <nojunk@knology.net> - 2016-11-03 09:57 -0500
      Re: 50 ohms to 0.02 ohm transformer amdx <nojunk@knology.net> - 2016-11-03 09:59 -0500
      Re: 50 ohms to 0.02 ohm transformer Tim Wescott <seemywebsite@myfooter.really> - 2016-11-03 11:56 -0500
        Re: 50 ohms to 0.02 ohm transformer amdx <nojunk@knology.net> - 2016-11-03 12:15 -0500
          Re: 50 ohms to 0.02 ohm transformer Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2016-11-03 19:37 +0200
            Re: 50 ohms to 0.02 ohm transformer makolber@yahoo.com - 2016-11-03 10:49 -0700
            Re: 50 ohms to 0.02 ohm transformer amdx <nojunk@knology.net> - 2016-11-03 13:19 -0500
            Re: 50 ohms to 0.02 ohm transformer amdx <nojunk@knology.net> - 2016-11-03 13:31 -0500
              Re: 50 ohms to 0.02 ohm transformer Tim Wescott <seemywebsite@myfooter.really> - 2016-11-03 14:38 -0500
            Re: 50 ohms to 0.02 ohm transformer Tim Wescott <seemywebsite@myfooter.really> - 2016-11-03 14:39 -0500
              Re: 50 ohms to 0.02 ohm transformer amdx <nojunk@knology.net> - 2016-11-03 16:52 -0500
                Re: 50 ohms to 0.02 ohm transformer whit3rd <whit3rd@gmail.com> - 2016-11-03 18:00 -0700
              Re: 50 ohms to 0.02 ohm transformer amdx <nojunk@knology.net> - 2016-11-04 06:26 -0500
                Re: 50 ohms to 0.02 ohm transformer Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2016-11-04 15:20 +0200
                Re: 50 ohms to 0.02 ohm transformer amdx <nojunk@knology.net> - 2016-11-04 09:33 -0500
                Re: 50 ohms to 0.02 ohm transformer Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2016-11-04 21:21 +0200
          Re: 50 ohms to 0.02 ohm transformer "tom" <tmiller11147@verizon.net> - 2016-11-03 14:02 -0400
  Re: 50 ohms to 0.02 ohm transformer Winfield Hill <hill@rowland.harvard.edu> - 2016-11-03 10:25 -0700
  Re: 50 ohms to 0.02 ohm transformer Jeff Liebermann <jeffl@cruzio.com> - 2016-11-04 11:24 -0700
    Re: 50 ohms to 0.02 ohm transformer Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2016-11-04 21:24 +0200
      Re: 50 ohms to 0.02 ohm transformer amdx <nojunk@knology.net> - 2016-11-04 16:46 -0500
        Re: 50 ohms to 0.02 ohm transformer amdx <nojunk@knology.net> - 2016-11-05 12:37 -0500
  Re: 50 ohms to 0.02 ohm transformer mike <ham789@netzero.net> - 2016-11-05 02:29 -0700

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