Understanding the Common Mode Choke using LTspice

#61 In this video I look at the common mode choke and the types of noise commonly present in an electronic circuit. You have the differential and common mode noise but this choke is only good for one of them.
So how can it be used to filter out noise in a general?

Relevant link:

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Music:
Creative Commons — Attribution 3.0 Unported — CC BY 3.0

[okidoki]

Dear FesZ, I don't find a word to tell you how u simplify the problem and explain them in simple term. Excellent, tons of youtubers can not come near you. Go ahead.

[Sheevlord]

Thank you for explaining this in such an easy to understand way. I made a noise filter similar to the one shown at 11:02, and now I can use cheapo SMPSs with an audio amp without hearing hissing sounds from the speaker

[kaztros]

Thank you! Especially for the very helpful knowledge @ 9:52 for how common mode configuration avoids core saturation.

[muratacar]

"Hello, and welcome back" favorite phrase 😄😄

[ilyassargul]

One of the best comprehensible video about EMC Filter. Thanks.

[pao_MSTATOR]

Great review. Please note that for common mode chokes it is better to use not ferrite, but nanocrystalline material! There, the benefit is really higher for common-mode chokes.

[Chetankarkera]

Just brilliant !! I always search for different materials to understand electronics fundamentals more deeply ..now I can easily visualise by seeing these videos ! Thanks a lot and keep up your good work 👍

[caeserv]

Good Video, it is also required to understand the leakage Inductance from the CMC to the circuit. Your presentation with the comparison of various LTSPICE circuits are wonderful.

[andresgongoraYT]

I really appreciate your efforts. Great video!

[andyparadis]

Very good explanation, removes the mystery for a novice electronics nerd.

[ArjunAKedd]

Imho, if you look at the simple LC filter as shown in the circuit on the right at 3:36, the common mode noise still has a path to ground through C6 through the lower wire of the differential wiring. Hence, this noise comes through. However, the loop immediately to the right of the differential mode source is broken by the inductor at noise frequencies. Hence, you can't see the differential mode noise on that loop. When you add another inductor to the lower wire of the differential wiring, then common mode noise has no path to ground through C6, hence blocking the common mode noise.

[thezodiace]

These guy's videos makes Orcad Pspice look like a complete waste of money, LT is indeed powerful. Great video btw.

[hichamlhachimi]

Great video and the use of LTspice has made it more perfect keep going

[pao_MSTATOR]

The fundamental difference between the operation of a nanocrystalline core and a ferrite core lies in the absence of a resonance characteristic of ferrites at frequencies of 0.5÷2 MHz, and work on the absorption of RF interference, in contrast to the reflection of interference characteristic of ferrites, which is associated with a change in the inductive nature of the ferrite choke to capacitive and can create problems in the work of the IIP.

Increase in impedance and attenuation by 2 - 6 times,
High resonant frequency and wide bandwidth (up to 5 times),
Absence of many resonances in the frequency response of the impedance,
Reducing the leakage inductance by 2.3 - 3 times,
High saturation induction (1.17 T),
Excellent temperature stability (in the range from -60°С to +155°С the change in permeability is less than 15%),
Low active losses in the wire,
Wide operating temperature range: from -60°С to +100°С,
Reduction of volume and weight by 2 - 3 times.

[ilterkoksal]

Hi. The first circuit gives different results with different versions of LTSpice. LTSpice XVII gives the same result as your simulation whereas at Version 24, vp swings around 9V and vn swings around 0V. By the way, great channel...

[mcintoda]

I would also add that the differential mode inductance is due to leakage flux that doesn’t couple in the ferrite. Some CMC employ purposeful leaky core winding to have both CM and DM inductance. Compact power supplies make use of this.

[p_mouse]

Nice video, as always!
Btw, when using FFT windows, it's REALLY important to choice the right FFT windowing function.

Very often I see a lot of people (including colleagues) using the wrong type of window for the wrong type of comparison.
In this case for example we are mostly interested in the amplitude difference, not so much in frequency accuracy.
So a good window function would be something like a flattop.

Using the wrong type of window function can quite often really lead to wrong conclusions.

[cyberphox]

Awesome videos, your channel is a gem

[sheetalmekhale]

Nice Video, one can reduce the coupling factor from 1 to 0.99 or so, a common mode filter also filters difference mode noise due to the leakage inductance of the 2 coils, the leakage inductance works as the difference mode inductor.

[manish]

In practical case the inductance varies (due to change in permeability) with change in frequency. Can you let us know how to simulate such case in LTspice.