How to Identify an Unknown Ferrite Core
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- Опубликовано: 2 июн 2024
- Do you have a ferrite core, but don’t know what it is? Follow along with Mike Arasim, Product Manager for Power and Inductive Applications at Fair-Rite Products as he identifies two unknown Fair-Rite EMI suppression beads using basic, inexpensive, readily available equipment in a very not temperature controlled environment.
Link to the Toroid Permeability Calculator: fair-rite.com/toroid-permeabi...
Interested in learning more on how to determine the Material of a Ferrite Core? Click the link to read our newest paper on the topic: www.fair-rite.com/determining...
Test equipment used: Keysight 1733C LCR Meter. Flir DM93 Digital Multimeter. Mitutoyo Absolute Digimatic 6” Caliper. 10 turns of 26awg solid wire.
Starring
Fair-Rite P/N 2673002402 as Sample #1
Fair-Rite P/N 2643002402 as Sample #2
www.fair-rite.com/product/emi...
www.fair-rite.com/product/emi... 
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Thankyou Mike, that was educational. I have been a fan if Amidon/Fair-rite as a young boy. I am now 48 and continue to be.
Brilliant info. I've got a whole box of assorted ferrites that I'd use if only I knew the specs. But why don't the manufacturers just colour code them like they do with resistors and capacitors?
Exactly, or maybe write on them like with capacitors.
Would be a reason enough to buy from Fair-Rite instead of somewhere else…
Mike thx for sharing. I know it's been a long time since this video was released but these days NANO VNAs have come down in price to the point they are quite affordable and can do the impedance measurement over quite wide frequencies directly.
I agree with many of the commenters cores should be marked somehow. I believe that Amidon color codes their cores or they used to.
Again Mike thx for sharing and giving us a tool/procedure to characterize cores.
Very cool! Just the info I was searching for! Thanks & 73!
When I drop ferrite cores on the floor I no longer need to identify them...
Thanks for the video.
Thank you. Ferrites have been a big gap in my knowledge base. You are helping to solve that problem.
f = 1/(2pi*((L*C)^0.5)). If you know your frequency, then use a series circuit with a potentiometer with your LC part of the circuit. You can dial in your pot so that the voltage drop is the same, that the value as the same. And you know the value of C, just plug and crank on your calculator, or spreadsheet.
Really helpful. Thank you!
Nagyon szépen kőszönöm a tájékoztatást,régota keresem
Really good heads up on cores. Now I’m a little bit wiser. Thank you sir. 73 de GI8WFA.
Thank you. Subscribed.
😂😂 loved it. Tnx alot man .wish u best🙏
Hi Mike, Core sample 1 (MnZn) O.D. 62.08mm; I.D. 36.01mm.; Ht 12.89mm. Sample 2 (NiZn) O.D. 61.52mm; I.D. 36.30mm.; Ht 12.72mm. Each toroid was wound with the same 0.8mm diam. X 125 cm. long solid Silver-Teflon conductor that passed through each aperture completely for ten turns, spaced generally evenly along the surface of the toroids. The F-R spreadsheet your company offers for an Excel download operates well, and returned an Init. Perm. of 172.
Thanks for the reply- The NiZn core looks like it is probably 61 material that got hit with a magnet. But in regards to the other cores I would love to help offline, could you email ferrites@fair-rite.com so we can discuss and hopefully solve your problem! Thanks so much
Nice video
Interesting on the beads. Are these actually useful as inductors or only as interference suppressors? I used a Fair-rite bead to make up a 10 uhy inductor using a General Radio standard inductor as a reference. (The standard inductor is a relatively large air core unit.) But there was no correlation to how they operated in a tuned circuit! The general radio unit resonated exactly as expected but the ferrite bead inductor was significantly off, (over 10%) even though they both read the same on the LCR meter.
All ferrite cores have potential use as an inductor. A lot comes down to the frequency they are being used at and whether permeability there is sufficiently high and the losses are sufficiently low at said frequency. Some variation on the inductance over frequency can happen even if the 10kHz inductance looks the same between two parts. Core materials will dramatically change the over frequency performance. Often times, in a very non-linear fashion.
Very helpful video, I still have one core I don't arrive to identify. Resistivity I measure to about 14 Kohm and Initial Permeability is calculated to 60. What mix can it bee?
Hi Leif, If it is definitely a Fair-Rite core….. 67 material would be the most likely (could have previously been magnetized to account for the higher perm).
Mike, Watched this video over and over. When you get to entering the series L in your spreadsheet and we see the last column fill in with Initial Permeability I am lost. Looked at the F-R calculator and added the dims on the 2 cores I'm trying to ID, and came up with I-P reading in the last block that had nothing to do with anything on the F-R materials chart. Measured over and over. My supposed NiZn T240 toroid returned a 193 I-P, and my MnZn T240 toroid returned a 51 I-P. Sfc resist of the NiZn was 0.33nS (3.3G-Ohms) and the SR of the MnZn was 3.2nS (312.5M-Ohms). The sfc resist readings are in line with NiZn ands MnZn. The NiZn inductance was 22.4 uH and the MnZn was 5.9uH. Plugging these measurements into the F-Rite Calculator returned the squirrely readings in the little results box, and that's where the disconnection between
what materials these 2 cores were, happened. These complete measurements were repeated over and over. The toroids were weighed and measured accurately. The project is to wind a 43:1 balun transformer for 1.8 to 30 MHz, connecting to an end-fed wire, but not knowing the material of the toroids might mean wasted efforts and materials. '73 de W4HBM.
Hi there, how many turns he checked the inductance with on each core?
Ham’s have two main questions about Ferrite cores…
1. what is the best mix for choking hf common mode currents?
2. what is the best mix for hf step up / down transformers (aka baluns)?
hf being 1.8-54mhz
these types and winding are all over the place on the internet.
For HF common mode currents, 31 material should provide the highest impedance overall in that frequency range. At more granular (narrower) sections of that band, there are other less broadband materials that can improve on the impedance over that offered by 31 material. For transformers targeting lower losses, 67 material will exhibit the lowest overall losses in the HF band. Same as with the suppression cores, there will be some materials with higher performance in certain sections of the band. 67 material does trade quite a bit of coupling (permeability) for its low loss properties. A higher loss, higher permeability may be desired for certain designs. This is especially true for lower power devices. We will be coming out with a podcast in the next coming weeks to go into this more in depth so stay tuned! Hope this helps!
Using this test, I think I have a type 68 ferrite toroid core. Probably not much use for suppressing noise off a AC power inverter.
Are both Manganese-zinc ferrites and Nickel-Zinc Ferrites magnetic?
love that jimmy stuart accent
Thanks for this. Now properly armed, I may be able to suss out the unknowns in my junkbox.
Is the spreadsheet available for download?
Bob, you can download the excel file at : www.fair-rite.com/wp-content/uploads/2020/05/Toroid-and-Rod-Perm-Calc-003.xls
Mike, I've been looking for this technique for some time now. Very helpful! Hope to see more videos! Great Job!
Thanks a lot man ...but one more thing how to measure for EE cores and other geometries
Thank you Mike. But may I have the EXCEL spread sheet please? I could'nt work out the effective magnetic path Le ??
Jimmy, you can download the excel file at : www.fair-rite.com/wp-content/uploads/2020/05/Toroid-and-Rod-Perm-Calc-003.xls
Where can I download the spreadsheet you're using?
fair-rite.com/wp-content/uploads/2023/06/C1C2LO.xlsx
Hi Mike. Wonder if you have a sec to help me determine What I have here. I have some snap together ferrite that I was able to determine are nickel based material. They measure A=25.7, B=13, C=28.8, &D=13. I'm looking for the best way to run the impedance test to determine the core material. The only markings on this is on the plastic case saying FAIR_RITE VO. I'm assuming that's just the plastic case number. Thanks for you time de KA9TII
The V0 is just the flammability rating of the plastic. Impedance analysis is a bit more difficult. Essentially you’re going to need some way to genereate a signal and a way to measure the response of that signal. Some of the newer inexpensive Vector Network and Spectrum analyzers (Nano VNA or Tiny SA for example) have impedance analysis functionality built in to them. While not totally accurate, they are surprisingly good and should be more than capable of telling the materials apart. If NiZn, the core will either be 43 or 61 material.
What does the outsize of the core/case look like? Whether it is round or square or octagonal will help me narrow down on a part number.
Thanks,
Michael Arasim
@@FairRiteProductsCorp Thank you Mr. Arasim, for responding to my inquiry. It is square. I have a VNA, so I will investigate the impedance test. I'm not familiar with the procedure, but I'm sure I can find something on RUclips. Again, thank you so much for your time.
Which ferrite type is the most stable at temperature changes (permeability vs temperature)?
As a general statement, 67 material has the most stable permeability over temperature. Depending on the exact temperature range, there could be other materials that are more stable at particular temperature ranges.
@@FairRiteProductsCorp thank you for your response!
Why the manufacturer doesn't mark them in any good way is bad practice.
Link to the Toroid Permeability Calculator is not working any more :-(
The link should be working now :-) thank you!
Why not just print the mix on the toroid
You could probably use a cheap NanoVNA for measuring the inductance and resonance. They are as cheap as 50 bucks nowadays! 🙂
Why is it not possible to laser scribe mark them ?
Thank you for the comment! We don’t laser mark every part for several reasons. The primary one is that due to the color and finish of ferrite cores, The contrast on the text from laser marking is very poor. It is possible to darken the text through multiple passes or through using a very high power level. The problem with this is that utilizing higher power runs the risk of damaging the electrical properties of the ferrite through excessive localized heating. Making multiple passes with sufficient cooling time in an option but, it would be very time consuming and greatly add to the cost of each part.
@@FairRiteProductsCorp I use a series of color dots on identified cores. It helps greatly.
Why ferrite cores are not part number laser marked to make it easier? 😂 I'm just thinking what a mess it would be if a worker drops 2 different boxes of ferrite cores....
what is pc40 material?
PC40 is a 2300 perm MnZn ferrite most similar to our 78 material as a reference. It would generally be used for higher flux density power devices but, it could see applications elsewhere.
do you have any dealer in India??
Our complete listing of authorized distributors are found here: fair-rite.com/distributors/ and you can choose India as the region to find your options! Thanks!
@@FairRiteProductsCorp I had checked them but unfortunately they failed to reply... Also they don't seem to be interested in answering emails.... sadly will have to look for some other brands.
Oh no! If you are not getting what you are looking for we also have many different global distributors: Digikey, Mouser, Newark/Farnell, RS Components, and Kreger Components. @@siddharth4662
keysight U1733C farnell UK price as of 15/7/22 £520.48 = $614.17,not exactly a couple of hundred bucks by any measure.
A very simple solution would be to color code unless the pigmentation would alter the permeability....!!!
I looked, i found and from a reputable channel.
After weeks of scouring the entire internet for solutions, I stumble across the video.
The link paid for with a vial of toddler blood on the dark web, and my hope blooming as I finally read the sentence
“using basic, inexpensive, readily available equipment”
Then the guy pulls out an LCR-meter.
The video comes to an abrupt halt, and the only thing penetrating the eerie silence is the sound of me putting the shotgun barrel between my teeth.
Relief is flooding through my being, realizing that the microsecond of lead traveling through my brain is preferable to trying to identify an inductor that the manufacturer didn’t feel was important to mark.
If you'd paid for it, you'd know.
Easiest solution would be to mark these cores instead of just having them all be nondescript black hunks of material. Color coding, a number painted on, something.
nanovna $20