Re: inductor polarity

On Fri, 28 Feb 2025 10:01:44 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:

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.
>

Try this:

https://www.dropbox.com/scl/fi/5mcmrincxepmhkve64rse/kmp_1900r-2.pdf?rlkey=a1p10nn8lgecslf1k6cmlp5jb&dl=0

My module has just about 1" of allowable component height, so this
uses the volume well. And this shape will have good cooling in the air
flow.

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
>

If I swap the pins, namely reverse the current direction, won't the
mag field direction reverse?