Seeking Someone to Do a Ferrites Project

Very nice kit!

They are great problem-solvers, getting rid of unwanted oscillations and suppressing noise. For anyone curious, for a certain frequency range, they act like a resistance (at a very high-level). There are different kinds of ferrites for different applications, but specifically, this is for those intended for "suppression", which is what this kit is for, i.e. designed to have high(ish) resistance at certain frequency ranges. Other ferrites may be intended for "inductive" applications, use-cases would include oscillators for instance.

It's sometimes easy to know because for companies like Wurth, they will provide nice detail: the red dashed line shows the resistance component at different frequencies. Many manufacturers won't provide such granular information, they may just mention the resistance at specific point frequencies.

I only have one ferrite kit for suppression, which is pretty ancient, and therefore so far have just been buying specific ferrites and this limits experimentation.

Wurth has many nice kits. I recently purchased a couple of Wurth inductor and capacitor kits. It's been a huge time-saver, having a range of parts on-hand. Great learning experience too, having the range of parts to experiment with.

Coilcraft has really neat inductor kits too (but the Wurth ones have a bigger selection!).

They end up being a lifetime supply since (I believe) Wurth and Coilcraft will replenish the kit forever (provided the kit is used fairly).

"It's sometimes easy to know because for companies like Wurth, they will provide nice detail..."

But do keep in mind that the curves shown change when a bias current is applied (the analyser curves are for 0A dc bias), and also with a change in temperature (those will be for 25C). The former isn't too bad with smallish currents (10s of milliamps), but once a supply current gets to an amp or two the change (reduction of impedance and hence resistance) can be considerable (though it's very dependent on the actual ferrite material used for the bead).

"It's sometimes easy to know because for companies like Wurth, they will provide nice detail..."

But do keep in mind that the curves shown change when a bias current is applied (the analyser curves are for 0A dc bias), and also with a change in temperature (those will be for 25C). The former isn't too bad with smallish currents (10s of milliamps), but once a supply current gets to an amp or two the change (reduction of impedance and hence resistance) can be considerable (though it's very dependent on the actual ferrite material used for the bead).

Hi Jon,

I meant that it's possible to tell which ferrites are intended for suppression use from those curves (and at what frequencies), but as you say, ferrites are not precision in any way at all. Normally at least a minimum resistance is desired, and any higher is a bonus.

For the ferrites in question, they are SMD components (i.e. not bare ferrite that needs self-winding) and they have ready-made guidelines in the datasheet on how much current to pass through them, so it's fairly easy to choose a part, for at least room temperature. even though it won't be accurate, usually just as high a resistance as possible is desired at the frequencies of interest, so anything well north of that would be selected (if possible).

I noticed wurth have a spice model which includes DC bias, I have no idea what it includes as I get a 404

https://www.we-online.com/en/components/products/WE-CBF#742792005 

I get the 404 error as well.

Hi scottiebabe ,

I am very sorry that you get the 404 error. We just got a new webpage so not everything is working properly. I will update you when everything is working again. 

Hello, The reason I pointed it out is I thought it was an innovative simulation product to offer (it just happened to also 404). The website looks great! Thanks as always for the great customer support! Take care.

We are always greatful to get such feedback and insights. I will definitly share this with the team. Thank you and take care too!

 scottiebabe the link is now working again the team fixed it. 

This is wonderful! Thanks for getting the link fixed. I have only played with the model for a few minutes in spice but had no issues to get it to work, it looks great!

Thanks again