embedded ethernet
Archiver
Posts: 46,084
>how can i test the
> transformer on them to see what the ratio it is?
>
I think the formula is:
Np/Ns = SQRT(Zp/Zs)
Where:
Np=number of turns on primary
Ns=number of turns on secondary
Zp=impedance of primary
Zs=impedance of secondary
I think that you can just substitute Z with measured inductance of the
windings and make either Np or Ns as unity(1) and Ns or Np will give you the
turns ratio you are looking for.
David
> transformer on them to see what the ratio it is?
>
I think the formula is:
Np/Ns = SQRT(Zp/Zs)
Where:
Np=number of turns on primary
Ns=number of turns on secondary
Zp=impedance of primary
Zs=impedance of secondary
I think that you can just substitute Z with measured inductance of the
windings and make either Np or Ns as unity(1) and Ns or Np will give you the
turns ratio you are looking for.
David
Comments
I have been working on a embedded ethernet project for use with a BS2. Gary
@ www.embeddedethernet.com did a very nice project but is no longer making
any kits so I'v been trying to put together a board of my own. I could'nt
get my hands on the Crystal CS8900A-CQ so I'm using the Crystal CS8900A-CQ3
(3.3v ver.) I'v got all the parts I need except the ethernet isolation
transformer. Does anyone know where i can get one? It needs to be a 1:2.5 on
TX and 1:1 on RX I can't locate one anywhere, heck I can't even find one to
use with the 5v chip (1:1.414 TX 1:1 RX) I would be grateful for any help,
also I have a bunch of lan cards kicking around how can i test the
transformer on them to see what the ratio it is?
Mike
Thanks for that formula it will be a big help to me :-)
Original Message
From: David Covick <dac@w...>
To: PIC STAMP LIST <basicstamps@egroups.com>
Sent: Saturday, March 11, 2000 8:06 AM
Subject: [noparse][[/noparse]basicstamps] Re: embedded ethernet
> >how can i test the
> > transformer on them to see what the ratio it is?
> >
>
> I think the formula is:
>
> Np/Ns = SQRT(Zp/Zs)
>
> Where:
> Np=number of turns on primary
> Ns=number of turns on secondary
> Zp=impedance of primary
> Zs=impedance of secondary
>
> I think that you can just substitute Z with measured inductance of the
> windings and make either Np or Ns as unity(1) and Ns or Np will give you
the
> turns ratio you are looking for.
>
> David
>
>
>
>
> -- 20 megs of disk space in your group's Document Vault
> -- http://www.egroups.com/docvault/basicstamps/?m=1
>
>
>
You could probably use the under a $ ones from Mouser used in the audio field.
Big selection too..
From: "Mike" <Mike@m...>
To: <basicstamps@egroups.com>
Date sent: Sat, 11 Mar 2000 11:02:11 -0800
Send reply to: basicstamps@egroups.com
Subject: [noparse][[/noparse]basicstamps] embedded ethernet
>
> Hi Stampers,
>
> I have been working on a embedded ethernet project for use with a BS2. Gary
> @ www.embeddedethernet.com did a very nice project but is no longer making
> any kits so I'v been trying to put together a board of my own. I could'nt
> get my hands on the Crystal CS8900A-CQ so I'm using the Crystal CS8900A-CQ3
> (3.3v ver.) I'v got all the parts I need except the ethernet isolation
> transformer. Does anyone know where i can get one? It needs to be a 1:2.5 on
> TX and 1:1 on RX I can't locate one anywhere, heck I can't even find one to
> use with the 5v chip (1:1.414 TX 1:1 RX) I would be grateful for any help,
> also I have a bunch of lan cards kicking around how can i test the
> transformer on them to see what the ratio it is?
>
>
> Mike
>
>
>
> -- Easily schedule meetings and events using the group calendar!
> -- http://www.egroups.com/cal?listname=basicstamps&m=1
>
>
ron... the motor man...
Ronald Doctors
http://www.members.home.net/rdoctors
transformer for your chip. They are also good with samples.
Chris Waters
>
Original Message
> From: Mike [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Thf3vJ_5SRAKhMytHq13uFatoTvVazrEYRsyO7CCv3EbUtVfBN2v_eA_Jz_71yr1qGgogytiaz70]Mike@m...[/url
> Sent: Saturday, March 11, 2000 11:02 AM
> To: basicstamps@egroups.com
> Subject: [noparse][[/noparse]basicstamps] embedded ethernet
>
>
>
> Hi Stampers,
>
> I have been working on a embedded ethernet project for use with a
> BS2. Gary
> @ www.embeddedethernet.com did a very nice project but is no longer making
> any kits so I'v been trying to put together a board of my own. I could'nt
> get my hands on the Crystal CS8900A-CQ so I'm using the Crystal
> CS8900A-CQ3
> (3.3v ver.) I'v got all the parts I need except the ethernet isolation
> transformer. Does anyone know where i can get one? It needs to be
> a 1:2.5 on
> TX and 1:1 on RX I can't locate one anywhere, heck I can't even
> find one to
> use with the 5v chip (1:1.414 TX 1:1 RX) I would be grateful for any help,
> also I have a bunch of lan cards kicking around how can i test the
> transformer on them to see what the ratio it is?
>
>
> Mike
>
>
>
> -- Easily schedule meetings and events using the group calendar!
> -- http://www.egroups.com/cal?listname=basicstamps&m=1
>
>