EEVblog

[@EEVblog]

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

[@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... 😉

[@SeltsamerAttraktor]

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

[@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!!!!

[@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!

[@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

[@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 🙂

[@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.

[@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 !

[@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! ;-)

[@BlackPhanth0ms]

So is this what they call slapstick?

[@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."

[@mitch3064]

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

[@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.

[@svampebob007]

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

[@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. ;)

[@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!

[@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.

[@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

[@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.

[@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 ..

[@jjoeygold]

Terminate the BNC inputs and repeat the test?

[@JohnDoe-qx3zs]

Perhaps with cheapernet (thin Ethernet) termination dongles. Should fit right on and do 50ohm termination with 0 cable length. Note that there are two types of these terminators, for opposite ends of the coax bus.

[@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.

[@TheRealBobHickman]

Just a second... is it April 1st yet in Australia?

[@ats89117]

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

[@r3bers]

What if loudspeaker on near scope? I'll try with my rigol 1054z today.

[@EEVblog]

Would likely have to be very loud as it's not rigidly coupled, but would be fun to try!

[@zadrik1337]

Loud noises in a data center is a known problem. Google it and you will find many links, including a couple studies. In one case they did a test run of the alarm system on the halon fire suppression system. When the alarms sounded the big disk farms started experiencing a large amount of errors. Edit: search for "Loud Sound Just Shut Down a Bank's Data Center" and you will get a nice example. Oh, it was inert gas not halon, but it will kill you just as fast once all the oxygen is gone.

[@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.

[@swingsetmafia]

could you throw some rubber buffers around the PCB on the inside to try and dampen this? or some rubber around the BNC connectors?

[@uni-byte]

What's with all the noise on the Teks?

[@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).

[@z1power]

So this can affect my reading if I am making measurements during an earth quake?

[@c2ashman]

But what happens if you throw it on the ground?

[@MichaelBRothschild]

I have now been extensively using my RTB2004 for three days using both the touch screen and physical buttons and I have not seen this problem once. I have had two analog chan. probes connected and the digital logic channels for decode operations. I must also say having had my previous Rigol DS2000 series (not A) for over three years I have never notice that problem once. I would like to see the effect with probes connected?

[@AdrianLeviAU]

Whats a good scope for a back yard tinkerer?

[@EdwardLehman]

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

[@Kyle-Veilleux]

im sure there is a reason you cant, but is it possible to mount the bnc connectors with braided wire to connect to the pcb? like how a voice coil on a speaker attaches? also maybe attach the pcb with rubber grommets like how a cd rom drive is mounted internally? would that reduce vibrations enough to work?

[@respomanify]

Question, why does oscilloscopes costs so much??? Because of their status as specialised equipment?

[@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.

[@RicardoUrio]

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

[@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.

[@voltlog]

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

[@rangdor]

could the bnc resonance be due to it being a "cap " by design. Could you use extention for to bnc to isolate it from the case and the board?

[@l3si0rek]

Isn't this the case that when you leave BNC open, not mechanically bonded, then the BNC connector makes the capacitor out of itself (except of the capacitors issue of course)?

[@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.

[@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!

[@Arek_R.]

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

[@a380rockerfan]

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

[@PhiTheProducer]

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

[@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.

[@whuzzzup]

7:31 why are the signal lines not straight?

[@junkerzn7312]

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

[@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.

[@ophello]

Does the siglent have some kind of active dampening or other wizardry to specifically screen out signals that coincide with shaking?

[@antigen4]

interesting - i wonder what the effect of having loud music playing out of a nearby speaker during signal acquisition would be...??

[@dougmanatt4317]

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

[@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.

[@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.

[@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.

[@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!

[@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?

[@sebastianb6439]

Expecto oscillorum!

[@dougspurell2387]

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

[@00Skyfox]

How many oscilloscopes do you have in total?

[@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.

[@ArumesYT]

My Uni-T UTD2102CEX has the same "problem", but I have to hit pretty hard to get 2-3mV spikes. It seems to be a high-frequency thing. It's easier to trigger with a light pen than with a reversed pair of scissors (steel blades in my hand, plastic handle on scope). Scissors have more mass so produce a lower frequency signal? Anyway, with the amount of force I have to tap the scope with, I don't see an issue with this scope to be honest. Nobody hammers their scope while taking measurements, right?

[@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.

[@stevecoatesdotnet]

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

[@DoRC]

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

[@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.

[@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.

[@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.

[@peterkjellstrom3100]

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

[@supersat]

This may be a naive comment, but does leaving the inputs floating make them more susceptible to this?

[@dougspurell2387]

Yes it does, totally. If Dave can demonstrate engaging the 50 Ohm Zin. The problem should lower in amplitude where it gets buried in the noise floor. Also it would be interesting if Dave engages grounding the inputs, this should eliminate the problem. If this stops the problem, it will lend credence to the problem just being the connectors and not the MLCC parts.

[@ganeshramdasari1812]

Hi Dave, I was just wondering.. aren't the BNC channels supposed to be vibration sensitive .. I mean .. if I connected my BNC probe to an accelerometer sensor to measure vibrations I would want highest probe sensitivity .. or perhaps this is a real problem where there is no avenue to redesign probes and BNC front ends .. would like some clarity on that.. or perhaps you can come up with a Gizmo like ucurrent that would counteract this effect if it is indeed deemed undesirable...

[@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.

[@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.

[@saddle1940]

Wht happens if you try this scope when testing audio speaker systems (100w amplifiers).

[@TheRecocebo]

isn't it like when a pin is disposed to air it gets noise but if pulled up or down by a resistor.

[@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.

[@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.

[@DrZoidbergism]

you could try to find the rsonance frequency of the mainboard with a speaker and a frequency generator

[@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.

[@LaurentLaborde]

The TELEDYNE is beautiful

[@qwertyasdf66]

I wonder how much of the noise floor is just vibrations from the fan.

[@davidjones3635]

I used to think valves were microphonic?

[@veraxis9961]

They most certainly are.

[@davidjones3635]

Any thing with a high impedance input will have a high degree of microphony . cables and so on!

[@shakaibsafvi97]

What about the new Agilent Technologies infiniium DSO-X 93204A 32GHz ????

[@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 :)

[@MarkTillotson]

Can you sample audio without a lead then? Turn up a good bass amp!

[@philhirst2434]

Nice to see the Siglent Blowing them all away!

[@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.

[@SevenDeMagnus]

The capacitors have become piezos?

[@twoody2148]

close to April 1 ?

[@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 :)

[@andrewwhite1793]

Why is the ADC at 7:27 so SAD?

[@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.

[@spyingwind]

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

[@rdxdt]

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

[@keefebaby]

If you use a lump hammer what happens??

[@fly-lucky]

I have several scopes they all share this problem with varying amplitudes in the spikes none are as sensitive as as your rs scope