EEVblog

[@EEVblog]

Be sure to watch Part 2: kzbin.info/www/bejne/ZnrZY4ekfpV2b5o

[@SeltsamerAttraktor]

It's ok, Dave. If you don't want this microphonics plagued scope anymore, I'd take it :3

[@proluxelectronics7419]

It's the Seismograph option!!!

[@diegfb2001]

Uderated coment! hahaha

[@Wishmaster1183]

HAHAHAHA

[@matt79de]

Shhh... Don't tell 'em. Otherwise they may start charging us for it... 😉

[@mikeselectricstuff]

Me : "Doctor, it hurts when I do this" Doctor : "Don't do that"

[@EEVblog]

Quick, add it to the user manual!

[@krishna34674]

I like to say "Don't do dat den" ;)

[@MrYuuns]

Ç

[@tom7601]

"I broke my arm in two places!" "Stop going to those places."

[@gwc1410]

This is a common doctor statement. I told my doctor the seat in my car presses on my hip, the doctor said don't sit in the seat!!!!

[@dannyisdandy]

*Clicks on new EEVblog video to hear Dave's latest ramblings* *Amazed to see how sensitive today's instruments are* *Learned about SMD multilayer ceramic capacitors* Thank you Dave 🙂

[@steverobbins4872]

I once had a similar problem with a Bit-Error Rate Tester (BERT) I designed back in 2002. The problem was phase shift in my 2.5GHz clock, which was produced by a PLL that multiplied up the 156MHz system clock produced by a Temperature-controlled crystal oscillator (TCXO). There were 16 PLL chips, and each one got it's own 3.3V supply from a low-noise LDO regulator. LDO regulators typically require a few microfarads on their output for stability, and I initially used ceramic caps. When I tapped on the side of the chassis with a screw driver, the 3.3V rail went up (I think) by about 30uV, and it lasted about 1ms. This caused a problem known as frequency pushing, where the output freq of a PLL changes slightly in response to supply rail perturbations. I replaced the ceramic caps with plastic film caps, and the problem went away completely. Why would such a tiny freq change affect the timing so much? Because phase is the integral of frequency. A 1ms supply transient lasts for 156k clock cycles at 156MHz.

[@MaxKoschuh]

great conment. thank you.

[@francoisdastardly4405]

Very interesting comment. Thanks !

[@maxusboostus]

I think if someone started taping me with a stick and poking me in my eye, I would trigger too! :-) Poor things.

[@tin2001]

maxusboostus Need a safe space with all this triggering going on.

[@glumfish6862]

lol

[@faxen123]

watching a crazy aussie, slapping scopes for 18 minutes. what i am doing with my life?

[@AttilaAsztalos]

Well yes but once you see the light and start watching eevblog exclusively at 2x speed, it's only 9 minutes! Whoah, right...?

[@SwervingLemon]

@@AttilaAsztalos Dave at 2x sounds like a possessed squirrel.

[@JohnHill-qo3hb]

Rolling on the floor, laughing my ass off and pissing myself... Oh the jocularity...

[@AliHSyed]

and theres a part 2 lmao

[@basspig]

A crazy RICH Aussie!

[@mikeselectricstuff]

Turns out it's not a significant issue once you plug the probe in - only with an unconnected input.

[@AndreMillerF]

Thanks Mike, I was looking at those unconnected connectors the whole video and wondering the same thing. I'm surprised Dave didn't do a test with it connected.

[@MaxKoschuh]

thanks Mike

[@user-lp2op9uu1w]

Tested it with 10x probes, still an issue with my scope.

[@kevy1yt]

mikeselectricstuff why would the probe being plugged in help the issue?

[@mikeselectricstuff]

The issue is that the voltage generated in the capacitor pushes a tiny amount of charge into the input, causing a voltage shift. Any capacitive or resistive load on the input reduces the effect by absorbing some of that charge.

[@l3p3]

13:40 Slapping always helps! At least on computers. I recognised the same effect a few years ago with my computer. I opened audacity and slammed the table and I was surprised it recorded that without a microphone plugged in.

[@sysmatt]

Dave was talking about new channels, perhaps a "Scope Slapping" channel

[@EEVblog]

Winner!

[@jrobi47]

I "slap my scope" a couple times a week

[@stevensexton5801]

LMAO

[@laharl2k]

Thats my fetish :3

[@elandrildoendur1579]

@Dave: ... Winner! Chicken dinner! ;-)

[@mitch3064]

You are killing me Dave! Pulling out a couple dozen scopes, and I cant even come close to affording a scope.

[@glenslick2774]

While I nodded, nearly napping, suddenly there came a tapping, As of some one gently rapping, rapping at my oscilloscope door. "'Tis some visitor," I muttered, "tapping at my oscilloscope door - Only this and nothing more."

[@frankbuss]

I'll take it for free, if you want to get rid of this shocking problem :-)

[@youtubasoarus]

I'll add that i'd also be willing to take these pieces of crap off his hands. I mean i'll even pay money for them. ;)

[@seymourshabow]

nice to see what actually occurs when I repair my TV by slapping the side of it

[@WaltonPete]

seymourshabow That's more likely due to a 'dry' solder joint or poor connection that temporarily improves its conductivity due to 'percussive maintenance'! I doubt the piezoelectric effect is likely to cause any obvious changes to the operation of a television.

[@vladomaimun]

A fellow student jokingly suggested to investigate what happens when you slap an old TV as his coursework.

[@EdwardLehman]

So much actual info that can be used at work or home. Fantastic/brilliant.

[@tohopes]

"Shocking!" * checks to see it's not a Big Clive video

[@laharl2k]

well at least he didnt have to "try it out" xD

[@theLuigiFan0007Productions]

Plug it into a quartz crystal and give it a good smash with the hammer. XD

[@stonent]

No fanny flambeaux edition scope.

[@crapper1]

tohopes or a new photonic induction

[@1234garrett1993]

I watch big clive too, and ave. Check out electroboom for a really shocking channel lol

[@BlackPhanth0ms]

So is this what they call slapstick?

[@DielectricVideos]

As an experiment, do you think you could datalog the interference and extract an audio signal out of this? It would be interesting to see if the microphonic effects of the MLCCs are sensitive enough to actually work as a usable microphone!

[@junkerzn7312]

Wow, I learn something new every day! (starts wildly tapping on my siglent). Now for part 2. -Matt

[@kenfoland]

I have seen this effect in association with modern electric guitar effects pedal circuits. It's not something you want in an audio system. I have contacted Digitech about it, and they simply denied it's an issue with their design.

[@dougspurell2387]

Dave, I will call the manufacturers tech support in the morning, to get more info and feed it back. Agilent / Keysight is my first choice, but I will try the others if not satisfied. The caps used in my Tek 2235 are 3 types. Dipped Tantalums, disc style, and stick style. All are through-hole of course. I have the service manual for the unit with schematics.

[@CykasAppleTV]

It got me curious and I tried the same on my Rigol 1054Z. My results were different. Tapping the chassis did not trigger anything, even harder ones. Tapping the BNC did, but I had to tap it relatively hard. I bought it just a month ago, maybe different hardware version ..

[@svampebob007]

"planned a quick video" we both know that you're incapable of quickies.

[@DoRC]

we really need to see this done with probes plugged in. doesn't really matter what happens with them unplugged.

[@JohnHill-qo3hb]

Several years ago, my employer was considering a R&S signal generator for noise floor measurements, there were even two R&S sales engineers present when one of our lead techs demonstrated to the R&S types that noise floor measurements could not be done because of the high noise level on the signals from the R&S generator, the he demonstrated the same test using a very old HP 8640B sig genny, noise floor measurement successful.

[@samsunghandy7892]

Awsome Video as always! I have seen almost every single episode while playing around over the years. Now I'm on the ee train, too. Thanks Dave :)

[@philhirst2434]

Nice to see the Siglent Blowing them all away!

[@hellnawnaw]

I've just whacked and prodded my DS1054Z like crazy, and couldn't get it to trigger via the chassis. Directly on the BNC it works just like you show, but I couldn't get it to trigger even once via the chassis. I've tried different pens and positions, I even tried smacking it right next to the chassis.

[@raymundhofmann7661]

Not only MLCC do this, also chips do it, especially if they are in small packages. Opamps "drift" with mechanical stress. On chip oscillators (ring oscillators, etc.) have microphonics. The timebase thus might be significantly microphonic, which could also be evaluated.

[@examplerkey]

Dave you are a legend.

[@a380rockerfan]

The Keysight DSOX1102 was actually configured for 20mV/div, not 2mV as you claimed it to be while you were tapping it

[@jerrymckee4332]

Been in electronics for years, this is nothing new... But good to show the young ones...

[@cmjones01]

Out of curiosity, I tried this on a properly analogue scope. Tektronix 7603 mainframe, 7A13 vertical plugin (differential, 100MHz bandwidth, up to 1mV/div sensitivity), 7B53A timebase. Set to 1mV/cm, 2ms/cm, normal trigger, input DC coupled but no probe connected. I couldn't get it to trigger by bashing the case, or at least I couldn't find a blunt instrument heavy enough to affect it, but tapping the input BNC connector hard with a pen did make it trigger. It really had to be actually on the connector, though, and the resulting trace on the screen didn't seem to be more than half a division high. That's probably a benchmark for low microphony.

[@Gameboygenius]

EEVblog #983 - A Shocking Oscilloscope Problem! (Gone wrong!)(Gone sexual!)(You won't believe what happens next...)

[@macdonalds1972]

Dave would never post clickbait.

[@Gameboygenius]

It was a first impression before watching the video. The problem was indeed shocking as it turned out. :)

[@natedunn51]

(Gone youtube restricted)

[@SianaGearz]

Yes, clickbait. I expected the scope to give Dave an electric shock from the title, but bad microphonics? Interesting, but not literally shocking.

[@Gameboygenius]

Find out how this single mom made 20.000 waveform captures in just one second. (Tektronix hates her.)

[@DIYerGuy]

Absolutely Shocking

[@mrpetit2]

Interesting to see that results differ so much and that some budget models/brands (like the siglent) perform way better than some very expensive models/brands.

[@DrGreenGiant]

hitting the BNC isn't a test of the mlcc because you're transferring charge between the pen and the sense circuitry, which is what it is designed to do. tapping the case though, wow, that's something to bear in mind for the future!

[@voltlog]

My DS1054Z does it very similar to yours: CH1 higher sensitivity than the other channels.

[@SatyajitRoy2048]

Not sure because I am not front end designer, but may be differential noise cancelling techniques need to be applied in order to cancel such piezo effect. At least for those scopes having touch screen and Dave like users. OR passives need to be reinvented to kill such effects. This is the place where you will find so many interesting things.

[@dougmanatt4317]

Mr Jones, you must answer truthfully! When did you stop beating your scopes?

[@absurdengineering]

Ceramic caps in the signal chain. Pretty typical. That’s where special construction techniques come in. It’s possible to work around this problem, but it requires quite a bit of experimentation to get it right.

[@vincei4252]

Just tried this on a HMO3054 and no issue. I find I tend not to whack the oscilloscope anyway :-) Same with the Spectrum analyzer - no pugilistic tendencies towards them, too much money to replace or repair :)

[@LaurentLaborde]

The TELEDYNE is beautiful

[@dismayer666]

No such issues on my Siglent SDS 1022DL :) Hit the crap out of my scope at different settings and didn't get such false readings.

[@sdttnkara]

The front cover of Siglent scope is not touching the BNCs there is gaps between plastic front cover and BNCs. The front cover of other scopes are all touching the BNCs and maybe they are fastened mechanically. It transfers the vibrations through plastic cover.

[@dougspurell2387]

Dave, I just checked my venerable Tektronix 2235 analog scope. It is doing the same thing.

[@dougspurell2387]

Hi Dave, it's 3:11 am here and testing your finding resulted in me up and about. I believe I can duplicate it here as below. It would be good to see it duplicated there as I am not set up yet to do this. No components other than the coax terminated in connectors at each end. I used a short piece of coax, terminated in connectors about 8 inches long. It should be as short as possible to not become a transmission line to the impulse frequency (probably not much chance of that as it is a mechanical force). One end to channel 1 of my Tek 2235. The other end mechanically isolated to not pass any vibration to the instrument. Henceforth, any slight impact, such as light tapping, to the isolated connector shows up as a pulse and triggers the scope.

[@denny9931]

Is that behavior consistent when attaching a typical probe? I mean you observe that with open inputs.... but probes are usually terminated, compensated, therefore provide some additional load to the input circuit. Which would mean that unused BNC´s would need to be terminated to not bounce that way to avoid that (probably no one does that).

[@lanceallen5092]

All joking aside, thanks for the heads up.

[@Meiestrix]

Is it maybe some electrostatic effect when you hit the BNC with the plastic tool?

[@jongyun23]

Meiestrix dave tried to hit bnc by plastic tools(might pen) weak and strong.. when soft touch doens't shown. but more.. figure out these noise. Anyway. Doc would say Don't try that.

[@thomasmaughan4798]

My Keysight DSOX1202X is immune from tapping on the scope itself BUT I have noticed environmental capacitance effects holding the probe and tapping my feet produces about a 50 volt DC impulse that peaks just as my foot reaches the floor, the velocity of rise increases as proximity to the floor, very much what I would expect in a capacitance situation with a DC voltage gradient in the room.

[@louisegreenwood8625]

Are you sure that some of what you're seeing isnt actually triboelectric noise generated by the BNC connector itself when you whack it? It would be interesting to do the same test hitting a BNC connector on the end of a length of cable, so it's mechanically isolated from the scope. Great video though!

[@louisegreenwood8625]

So, I just tried the following : Put a BNC T-piece onto a short BNC lead, and plug the other end into my old HP1740A 'scope. Tapping the T-piece with the hard plastic handle of the screwdriver I was able to generate spikes of almost 100mV pk !! Seems to me that a good proportion of the effect that Dave's seeing could actually be the BNC connector itself, generating triboelectric noise. An easy test that you can try for yourself!

[@ronshaw80]

Actually, the new Owon XDS series scopes have 12 bit resolution. If you go for the 200MHz version, you get 14 bit resolution. I just picked up the XDS3201A through Amazon for $550 US. 12 bits, with the battery, DMM, touch screen, decoding and other options included. So far so good.

[@RicardoUrio]

Hi Dave, Keysight DSOX1102G was configurated to 20mV / div

[@Herby-1620]

It might be interesting to do these tests with the BNC inputs shorted or with a scope probe to see if there is any difference.

[@andywilliams2085]

I dont often use my scope without the leads plugged in. Perhaps the damping when the mass is increased takes the noise floor down. Its the old Mass Spring Damper problem from control theory.

[@UmbertoFellinni]

You have a very good set of measuring instruments. It's so cool! I would also like to have so many instuments.

[@jasondoe2596]

LOL, that was admittedly unexpected (and very interesting - I'd never have guessed some scopes were this susceptible to vibration).

[@embeddedgirl]

I've had a similar effect when flinging a mic cable around at fast paces, as if I used it as a whip. If you turn the gain up on the console to full (most analog boards will have about +75dB of gain on the Mic inputs) you can actually here the effect going through the board.

[@dougspurell2387]

Check out Triboelectric effect which will put noise on a conductor due to high insulation resistance. A small noise voltage is produced when the insulation rubs against each other (as when you are flinging them around).. This appears riding on the mic signal and gets the same 75dB of gain. Cables that are used to eliminate the effect have insulation that is slightly conductive.

[@every1665]

I know that with my 20 year old Tek 2024b scope, if I hold the supplied probe tip within a few inches of the back of the scope it's noise a-go-go. But I haven't yet tried using it as a set of bongo drums while capturing any signals.

[@N1RKW]

This isn't just an issue with modern/digital scopes. My old HP 1980B scope (from 1982-ish) shows the same issues. To a lesser extent, my ancient HP 120B (early 1960s?) does also despite being so old it came with banana jacks instead of BNCs. Any scope with ceramic caps in the front end will do this, I suspect.

[@crackwitz]

shout at it!

[@jani140]

He definitly smashed his spys headphones. :) Dave revealed DSOs as the most vulnurable autospy bugs in the lab!

[@PhiTheProducer]

Those waves are the oscilloscopes screaming, because you keep hitting their nuts with a stick.

[@johnnyprimavera2]

Now you have your own set of scope-o-drums, just hook the trigger out signals onto a synthetizer.

[@peterkjellstrom3100]

Would be interesting to see if the most sensitive ones could even be affected by music or loud noises.

[@bit2shift]

The DSOX1102G displayed "Trig'd?" when Dave whacked it with his hand.

[@innopriest]

Aside from the HP which didn't have the case on it, and the tek MDO3000 looks like the more sensitive it is the more likely it is to pick it up. Maybe some mechanical decoupling or compliant mounts are in order.

[@jannb.6811]

It seems like RIGOL fixed it a little bit. Triggering by nocking on the case seems to be a bit harder. The BNCs are still a lot microfonic.

[@dougspurell2387]

One more comment. Mikeselectricstuff said this behaviour is not there if a probe is plugged in. This is correct, at least on my Tek 2235.

[@unfa00]

So the capacitors act like capacitive microphone capsules? Awesome!

[@trophosphere]

The oscilloscope is just showing the signal you inject into the system whenever you perform percussive maintenance on a device you are trying to get working.

[@God-CDXX]

I just tried this on my Techtronic's 555 this beast faired very well

[@zx8401ztv]

So dave, "There's scope for improvement." :D

[@sebastianb6439]

Expecto oscillorum!

[@JerryWalker001]

Digital Scopes have always done this. We always locate our scopes on a shelf above the workbench. On some spectrophotometers I used to work on that had glass photocells we even had to stop talking to make sensitive measurements.

[@muppetpaster]

1:29 Conclusion: Never whack your probes onto device under test.

[@jacks5kids]

Ceramic capacitors are by no means the only source of these transients. If you take a coaxial cable that obviously has no ceramic caps in it, connect it to the scope and tap the far end with a pencil, you will still trigger the scope. Plastic-metal interfaces also generate microphonic transients when tapped.

[@MaX271]

Good to know when you're on the field with rattling machinery around!

[@dmwtech4495]

Hi Dave, thanks for this info. this could be a potential issue when testing things in a environment that is creating such vibration shocks. in the auto repair arena, these type of scopes are starting to being used to diagnose network issues, and if your scope has this problem, when you are monitoring a can issue, driving down the road, hit a bump, see a hiccup in your signals, you might be inclined to think you found the problem with a possible circuit connction, when in fact nothing happened and your scope induced this fault. could make you chase ghosts. a lot of times in this scenario unused channels will not have probes attached. again thanks.

[@Arek_R.]

I got over *2Vp-p* when I used plastic fork on my toy-scope from owon sds5032e

[@luisapbarbosa1366]

I always suspect from this near April 1st.

[@rdxdt]

Lessons that i learned: - oscilloscopes aren't supposed to be used as drums. - oscilloscope probes aren't supposed to be used as drumsticks

[@hydrochlorotiazyd]

Or explanation is in other place, Dave often show that found new full opt. scopes in local dumpster? Mayby it had to be too beautiful that somebody dump the new good scope like this :P

[@CLipka2373]

"I _think_ that's every scope I have in my lab, I'm not entirely sure" - talk about hoarding ;-)

[@rbmk__1000]

Wow,I have never considered this phenomena before, would make delicate measurements in a high vibration environment rather difficult, maybe not a concern for bench-top models but in a portable that may see use in an industrial setting..... it would be interesting to see if the fluke portables, for example are effected, maybe with harmonics of 50/60hz as found in equipment or spaces one might need to measure.

[@ams718]

My Teledyne LeCroy WaveRunner 64Xi has a surprisingly good isolation. I've set the trigger level to 1mV and no matter how or where I whacked it (the case, all the BNCs, the screen) but there is no capture. One thing to note, however, the fan is pretty loud and for this reason I believe the engineers might have paid a special attention to this matter when they designed the front end. UPDATE: I used 1MΩ impedance inputs.

[@spyingwind]

The real question. Can this be turned into a drum machine?

[@charleslauter5035]

Oh well, Back to my old analog Tektronix scope.

[@nameis6895]

EEvblog Hit the scope section!

[@gregcooler]

try the RTO2024 2GHz BW, 20GSa/S, even better. Cost about $15k with trade-in. Awsome!! Can't wait to see some tear down of that.

[@AlexKall]

Positively surprised by the siglent!

[@krmlzr1079]

You make drumming so much more expensive like this!

[@any1ne]

- Doctor, when I press in this place, it hurts me a lot. What should I do? - Don't press! 🤣

[@ats89117]

How do you know that the problem isn't being caused by triboelectric noise from the input connectors?

[@limon93studio]

What about noisy fans inside? They can be a big source of vibration too. Maybe a comparision of the noise level with and without fans powered?

[@stevec5000]

The optional earthquake detection feature is not a bug, it's a feature!

[@stevecoatesdotnet]

Interesting video Dave. Do you get the same effect on Analogue scopes?

[@DocMicha]

couldn't it be the bnc connectors, which jiggle around if you shock the scope? This will also change the capacity. You should check it with bnc cables connected.