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From: Jeroen Belleman <jeroen@nospam.please>
Newsgroups: sci.electronics.design
Subject: Re: inductor polarity
Date: Fri, 28 Feb 2025 10:01:44 +0100
Organization: A noiseless patient Spider
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On 2/28/25 04:50, john larkin wrote:
> I need to put 16 of these on a very dense PC board.
> 
> https://www.digikey.com/en/products/detail/murata-power-solutions-inc/19R476C/5798223
> 
> Each of the eight channels needs two of these. If I can put each pair
> of inductors close together and with the same current but opposed
> field direction, I'll get minimum mag field leakage to other channels
> (and to other boards.)
> 
> I see that one lead is longer than the other. I wonder if that implies
> a consistent winding direction, so my manufacturing people could use
> that as the "pin1" indicator.
> 
> If that's not dependable, I'll have to set up a rig to determine mag
> field polarity, and mark one side with a red dot or something.
> 
> I'd rather use surface-mount shielded inductors, but these tall
> unshielded drum cores have way more L and less R than a shielded part,
> for a given PCB footprint.
> 

I can't see the Digikey link. They want me to switch off
my adblocker, which is just no.

If this is a solenoid, turning it 180 degrees is not going
to make any difference! It will still be the same winding
direction!

Jeroen Belleman