ferrite vs iron powder

Discussion in 'General Electronics Chat' started by lokeycmos, Aug 11, 2011.

  1. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    is there a way to visually tell the difference between ferrite and powdered iron cores? i have a box full of round and rods and just wondering.
  2. SgtWookie


    Jul 17, 2007
    If they have a part number on them, you can sometimes find who made them, and then their specifications.

    There is "sort of" a standard color coding used on powdered iron cores, but the ability to order toroids with any color you want on them (or uncolored) pretty much negates going by color.

    If you just have a pile of them, you can start by wrapping on 20 turns and seeing what their inductance is. That and the dimensions will give you a starting place towards finding out what they really are. But, you really need to take measurements over a fairly broad frequency spectrum to find out where their Q peaks.

    For example, a T50 #6 material toroid will have its' peak Q (~220) with 25 turns wrapped on it @ ~9.5MHz. By 12MHz with 19 turns, the Q drops off to ~205. Down at 4MHz with 62 turns, Q drops down to around 200. Different materials have different Q curves.
  3. bertus


    Apr 5, 2008
  4. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    A magnet will stick to the iron powder cores but not the ferrite ones.
  5. Willen


    Nov 13, 2015
    Maybe not completely true. I have tens of cores from line filter, choke, LC tuning circuit, AM loop stick, SMPS transformers etc and all of them stick to the magnet.

    The thread is old but maybe I found the easiest idea. We can test its softness by knife. Ferrite Core is really HARD material but Iron Powered Core (normally painted) is so soft material.
    Last edited: Jul 25, 2017
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