EEVblog #855 - Ceramic Capacitor Piezoelectric Effect

[Neilm]

What's the best approach to find "guilty" part if you have board with tons of capacitors, coils etc - like some laptop mainboard? Using ear doesn't work, too high frequency, so unable to locate.

As a first pass, I have used a piece of paper rolled into a tube.

[wraper]

Is there anything wrong with that?

Nope, perfectly fine.
I just got an impression over the last few videos that you made your own multimeter (you kept mentioning a "secret project" here and there for the past few months) and the illusion went splat on this video.

There will be true eevblog meter. This Brymen meter has nothing to do with it.

[strangersound]

What's the best approach to find "guilty" part if you have board with tons of capacitors, coils etc - like some laptop mainboard? Using ear doesn't work, too high frequency, so unable to locate.

As a first pass, I have used a piece of paper rolled into a tube.

Not a bad idea. 

One can also get test microphones (usually electret condensors) with extremely wide frequency ranges (1Hz-200kHz) that I would guess you could use to zero in on a sound source by sweeping it in close range across the board.
ref:
http://www.aco-japan.co.jp/eng/Meas-Mic/meas_mic.html
http://bertrik.sikken.nl/bat/mics.htm

There are also a number of web articles and even a thread in here somewhere about how to use a mic with an oscilloscope.

[Barny]

Another methode is the "pokeing methode"

Use an hard, isulated object like a wooden spoon,... and press towards possible noice source.
If it gets silent or the frequency changes, the culprit is found.

Another way is to press a ear towards the wooden spoon while pokeing around.
That helps to identify different noice sources.

[nwvlab]

even with C44 removed, I can still hear a very very faint whine coming from somewhere (only with the case open, and even then it's faint), probably from C43.

Not probably, 100% certainty. There is nothing else in the backlight circuit.

Couldn't be the remaining faint whine coming from the piezo buzzer, getting some signal (well, the electrical noise from the charge pump) through cross-talk? (or due to poor bypassing)

[MobileWill]

Thanks for the great video. I got a chance to use the meter last night for a new project and hadn't noticed till I bent over my workbench with my ear closer to the meter. You published the video just in time. I think in my case I will just leave it alone. I can't hear it unless I have my ear up to it. Which shouldn't be often.

Great learning experience though.

[Fungus]

What's the best approach to find "guilty" part if you have board with tons of capacitors, coils etc - like some laptop mainboard? Using ear doesn't work, too high frequency, so unable to locate.

Get a piece of tubing. Put one end in your ear and the other end on the suspect component.

(like a stethoscope...)

[Fungus]

Is there anything wrong with that?

Nope, perfectly fine.
I just got an impression over the last few videos that you made your own multimeter (you kept mentioning a "secret project" here and there for the past few months) and the illusion went splat on this video.

That's a different meter, still in the pipeline.

[SilverSolder]

What's the best approach to find "guilty" part if you have board with tons of capacitors, coils etc - like some laptop mainboard? Using ear doesn't work, too high frequency, so unable to locate.

Mechanics use a stethoscope with a solid steel rod to locate noisy bearings etc. in engines, it might be good for finding noisy electronic components as well (maybe after wrapping the rod with some heat shrink to insulate it!).

Example:  http://www.harborfreight.com/mechanics-stethoscope-69913.html

[Brumby]

Mechanics use a stethoscope with a solid steel rod to locate noisy bearings etc. in engines

I actually have one of those.  I might see if I can dig it out and try it on my 235.

[f4eru]

You can use that :
https://product.tdk.com/info/en/catalog/datasheets/mlcc_automotive_megacap_en.pdf

or put the cap on two little wires

or put cutouts in the PCB around the cap...

etc...

[Brumby]

or put the cap on two little wires

That's what ran through my mind ... compliant mounting.

[hopski]

or put the cap on two little wires

That's what ran through my mind ... compliant mounting.

Yeah, but if you wanted do it right then you'd have to seal it in a glass bubble and pump all the air out.   

[vsboost]

So... What's the point of these multimeters if it's just a re-branded unit that you "don't have a schematic of", as said in this video?

I like the meter, I want to sell it, I think it's good enough to put my name on it, I think it's cool to have a meter I can use in my video that has my brand on it, a lot of people get a kick out of having an EEVblog branded meter, and it helps feed my family. Is there anything wrong with that?
If you don't want to buy one from me that's fine, buy the regular BM235 (I deliberately didn't hide the fact that it's the same as the regular BM235). If you do want to buy one from me with the EEVblog name on it, then great, here it is. If you think its crap, that's fine too. Name an equivalent model meter on the market that you can officially get the schematic of.

I definitely get a kick out of owning an EEVBlog product, i posted a pic of it in use on a facebook group I'm a member of regarding SDR's and a few people noticed the meter and mentioned Dave (just goes to show how popular you are lol) Also the meter is fantastic and so accurate compared to the other cheap ones i have been using for years and has an awesome feature set.

I also purchased it because i get hours of FREE entertainment from Dave's videos and i like to show my support.

[rrinker]

or put the cap on two little wires

That's what ran through my mind ... compliant mounting.

Yeah, but if you wanted do it right then you'd have to seal it in a glass bubble and pump all the air out.   

 Would that then make it a vacuum tube voltmeter?

[HAL-42b]

Would that then make it a vacuum tube voltmeter?

  I'd buy that.

[Barny]

What's the best approach to find "guilty" part if you have board with tons of capacitors, coils etc - like some laptop mainboard? Using ear doesn't work, too high frequency, so unable to locate.

Mechanics use a stethoscope with a solid steel rod to locate noisy bearings etc. in engines, it might be good for finding noisy electronic components as well (maybe after wrapping the rod with some heat shrink to insulate it!).

Example:  http://www.harborfreight.com/mechanics-stethoscope-69913.html

To use a metal rod with an electronic component isn't a good idea.
Thats why I use an wooden spoon (and hope I dond get cought for abuse cooking utensils) or a wooden rod.

[f4eru]

To use a metal rod with an electronic component isn't a good idea.
Thats why I use an wooden spoon (and hope I dond get cought for abuse cooking utensils) or a wooden rod.

You can glue a ceramic pellet at the end to isolate it electrically while still transmitting vibrations...

[mc349iii]

Did anyone try soldering a LED to the empty pad?  Seen early in the video.   Presumably that's the serial output signal,  it would be nice if there is a signal being sent.

[Brumby]

Would that then make it a vacuum tube voltmeter?

  I'd buy that.

+1      

[fanOfeeDIY]

Hi,

I am basically earning my income with software engineering area but I used to work for Japanese Manufacturing company and experienced the sound of Ceramic Capacitor.

Major companies of Ceramic Capacitor have web pages for this effect and provide capacitor series with less effect.

Murata
http://www.murata.com/en-global/products/capacitor/mlcc/solution/naki
(Video is kind of Jinglish)

Taiyo Yuden
http://www.yuden.co.jp/ut/product/tech/faq/q018.html

TDK
https://product.tdk.com/info/en/products/capacitor/ceramic/mlcc/technote/solution/mlcc02/index.html

[SeanB]

Compliant mounting ( blob of acetoxy free electronics grade silicone)  on the capacitor, or simply using a different manufacturers part ( or even a different batch) will probably lower the noise, along with using a different capacitor type, a small film unit might fit, or a PCB mount electrolytic using the same pad spacing.

[Bud]

What's the best approach to find "guilty" part if you have board with tons of capacitors, coils etc - like some laptop mainboard? Using ear doesn't work, too high frequency, so unable to locate.

Perhaps use another shitty ceramic capacitor wired to a scope or audio amplifier. Tape the wires to a cotton swab rod with the cotton part cut or to a sushi chopstick  to make a probe

[EEVblog]

Is there anything wrong with that?

Nope, perfectly fine.
I just got an impression over the last few videos that you made your own multimeter (you kept mentioning a "secret project" here and there for the past few months) and the illusion went splat on this video.

You are not a supporter who's "in the know" 

[Fungus]

Have you shown this video to Brymen? If so, what did they say...?