How to solve EMC problems! || The mystery of the buzzing speaker

You can find the products shown in the video below:

In this video we will solve the mystery of the buzzing speaker. The reason for the noises are of course EMC problems, aka electromagnetic compatibility problems. That is why I will explain the reasons for EMC problems, how to measure them and how to fix them as well. While doing so, I will not only talk about mains filter but also about other areas of the EMC. Let's get started!

Thanks to the Würth Elektronik eiSos Gruppe for supporting this video.

Music:
2011 Lookalike by Bartlebeats
Killing Time, Kevin MacLeod

[SLLabsKamilion]

Wow, rare to see a video with such a chill sponsor. Great job Würth, thanks for your hospitality!

[deadbird]

As a bass player I've had such a problem lately because of a cheap PSU causing an annoying electrical hiss at high volume, which is amplified when I use distortion pedals, and I almost always do. Thanks a lot for this video!

[dlcy]

After 1 minute of the german version of this video i switched to english - even i am a german native speaker, this german voice is so unfamiliar to me :-)

[shimonelstein]

Thanks for a great explanation. I'm a physicist / engineer. This was always a mystery to me, especially the common mode vs differential mode. You really cleared it up.

[carlosruizmora]

You definitely raised up the bar with this video. It kept me absorbed for its whole length (despite I was in the office). Thanks a lot, keep bringing more videos like this one.

[herpingscienceandmore]

Hi great Scott you’ve told me a lot about electronics thank you for everything

[der_pinguin]

Your English has changed so dramatically since I first watched you.

Good work, and thank you for all the videos.

[Magic-Smoke]

Thanks for bringing up this very important topic. In most of the maker designs we see here on YouTube and elsewhere, EMC is never mentioned. Yet it affects us all on a daily basis, from interference on audio to degraded WiFi or other equipment performance. Moreover, you can even, unknowingly, affect your neighbours. I have friends who have tracked down interference on audio to faulty/cheap/nasty SMPS several houses away!

[joczo]

This is incredibly useful for ham radio ops

[anmesh]

When you're so early, the title changes in front of you (from German to English)

[therandomchannel]

Awesome! Würth did a great job advertising here

[thlchmst]

Great explanation. This is a solid reference for future research on my EMC problems. This video go straight on my electronics playlist. Thank you very much for sharing this.

[brianogram]

This is great information to share with amateur radio operators too. We're always chasing down RFI. Thanks Scott!

[SkyhawkSteve]

I've used Wurth filter components in my professional life, and they have been very good. I'd also recommend Fair-rite for ferrite devices. For this sort of interference, adding a filter will get the job done but adds cost. If this was a production situation, the first goal is always to fix the device emitting the noise. For the hobbyist getting their first exposure to EMC, this is a fine introduction.

[pauljackson]

This video gave me better knowledge about EMC topic as compared to my book on the same subject...
Loved your video and thank you for making this topic memorable for me

[LorneChrones]

Great intermediate video into the world of EMC!. A good thing to remember is that signal/power integrity/quality are inversely releated to EMC problems, if you have a well routed signal (tight ground return, matched impedances, length matching on differential pairs, etc), then your signal integrity will be solid plus that particular signal will likely be EMC compliant and immune to external interference. Win-win situations like that are certainly possible and desireable. If you can catch them early in the design phase (schematic & layout) then you'll be saving yourself alot of frustration down the road.


Recommendation to definitely do a video on ESD / EFT in the future as that's another common EMC problem that EEs must face when designing products.

[Audio_Simon]

This was excellent! I had a very similar problem making powered speakers and buying a cheap PSU brick on eBay. A genuine Toshiba one was much quieter.

[ExStaticBass]

You might be a bit mistaken. In the recent past I have used the head stator from a hard disk, a darlington and MOSFET based amp, and a small speaker to check for EMR in many of the devices I've built. The stator coil on the head armature of a common hard disk is sensitive enough to pick up the flux field and creates a strong enough signal to be usable through a standard microphone preamp. The only issue I've found so far is frequency. As some audio devices filter out anything above 20KHz it's sometimes difficult to accurately find and diagnose such things as back EMC. This is why I would recommend building your own amps because you can omit such filtration. This might make an interesting episode of your series "Build or Buy" because it's been a pretty useful tool for me so far since I built it.

[LignumPower]

At beginning (1:00) there is noise when LED strip is put at 50%. In your final tests, the LED strip doesn't seem to be at 50%. If true, it is not a fair comparison as 50% would generate more noise. Never the less, it is still a great video on how to remove EMC.

[ExplodingWaffle]

suprisingly educational for a video i thought was mostly gonna be about the sponsored content. good work