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).

I made a switch mode buck regulator circuit 2 years back for my ESP8266-based smart home project. The rule of the regulator circuit is to convert 220V line voltage directly to DC, then convert to 5V DC, and finally to 3.3V DC using a 3.3V regulator IC. That time I missed the ferrite bead. Adding ferrites like the below circuit can be a good update. I can compare the output for both circuits. I also added two more filter capacitors to the new circuit. 

It would be interesting to see what changes are a result of the ferrites.

We are very happy to see that you are excited for the kit. 

Looking forward to your project ideas!

Best regards,

Nicola

Würth Elektronik 

Hi shabaz ,

Great to hear that you use our kits and our components already. When you want to have more details and opportunities on the components you can have a look at our online simulation platform REDEXPERT you can find it here: https://redexpert.we-online.com/redexpert/#/module/1076121

Best regards,

Nicola

Würth Elektronik

"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).

i have being using ferrite bead in my protoyping board sort of trial and error or best practice way and never attempted to understand its essential. definitely looking forward to an essentials article from E14. Having said that, the design kit contains various types of high current and high frequency EMI suppressing ferrite beads. Although i not sure how to deal and test with EMI, if i were to play with the ferrite beads, it would be in power supply related circuit. I would like to measure, visualize and hopefully understand the impedance change over frequency as per its theoritical charateristic. While i don't have a $30k impedance analyzer to play with, there exist low cost AD5933 based impedance analyzer module with controller board on site such as Taobao (https://www.taobao.com/list/item/673727667622.htm?spm=a21wu.10013406.taglist-content.4.38d420ae87uow2) . we can use a microcontroller / pc based I2C control to command the module to perform impedance analysis over a dc to dc converter. we can get various cheap dc-dc up converter (which has high frequency) from taobao, such as ADP5070 based module https://item.taobao.com/item.htm?spm=a230r.1.14.71.5e787b9094h5mC&id=587411536412&ns=1&abbucket=7#detail , and replace the ferrite beads on the board (they are SMD) and perform the impedance sweep over frequency. While this experiment is not geared towards circuit design, it seems highly doable on a tight budget of less than $100 and 3 weeks work

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).

nice to know there is an online simulator. have never know its exist because previously i only use ferrite beads based on sample circuit provided on application note. 

Hi Weiwei,

Nice find. I think that would work very well. The frequency range is limited, but in that range I think it would be awesome. I've wanted to build one using the AD chip for ages, but other things get in the way. Something ready-made like that sounds really neat.