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  • เผยแพร่เมื่อ 5 ธ.ค. 2024

ความคิดเห็น • 265

  • @andymouse
    @andymouse 4 ปีที่แล้ว +27

    6 years on and your 'deep dive' stuff is still pure gold, I wonder if the UNI's around the world use this in their curriculum..they should..cheers.

    • @seanwieland9763
      @seanwieland9763 2 ปีที่แล้ว +3

      8 years later, came here to say this. Evergreen content for sure!

    • @jaffers8593
      @jaffers8593 9 หลายเดือนก่อน

      9 years later and the sentiment is still the same! Rock on! 🎉

    • @robegatt
      @robegatt 3 วันที่ผ่านมา

      10 years still good stuff 😊

  • @jarrodhroberson
    @jarrodhroberson 10 ปีที่แล้ว +25

    Ignore anyone complaining about content being to long. youtube is littered with videos that dont' actually explain anything in any useful detail. You rock! I am a software guy for 30 years, between you, Mike, Bruce Simpson, Jeri Ellsworth and the young guys like Kevin Darrah and Jeremy Blum I am actually understanding the hardware that powers what I have been doing for a living since the 80's!

  • @Sunnyskyguy
    @Sunnyskyguy 9 ปีที่แล้ว +32

    Dave, you may think 20MHz is an arbitrary frequency, but it is also the point where poor probing methods with long inductive probe ground leads start to cause extra ringing on fast logic causing measurement errors.
    So for clarity 20MHz is for convenience when risetime induces false ringing from poor probing skills and gets a better textbook looking trace.
    For ideal trace remove probe tip and ground clip and only use tip and probe ring to a pair of test pins or wires of similar spacing for convenience or use the coiled ground spring accessory . This gives the best results using a 10:1 probe.
    Generally signals much less than 30MHz are used for this mode but logic rise times faster than 100ns ( most are) will get an overshoot proportional to the ground probe length and transition frequency resulting in ringing..
    Tony EE since 1975

    • @robegatt
      @robegatt 2 วันที่ผ่านมา

      @@Sunnyskyguy the probe tip and ground wire are handy when you are just looking for logic levels and you don't care about the shape being a perfect square

  • @eded8045
    @eded8045 5 ปีที่แล้ว +2

    no book could have given such memorable clarity on these pitfalls.... excellent video Dave and the best part is its a free video )))

  • @JanPedersen
    @JanPedersen 10 ปีที่แล้ว +6

    Totally agree with Jens Andree. These kind of videos actually makes a difference in the world for a lot of people. Thx Dave....more of this stuff :)

  • @ftester32
    @ftester32 10 ปีที่แล้ว +4

    For me one of the best videos from the EEVBlog series. Cannot really understand why two guys gave a thumbs down...

    • @tubical71
      @tubical71 10 ปีที่แล้ว

      actually they are four by now....i presume they do not give a damn on noise as they only play music *loud* ;)

  • @electronicinvestigations1253
    @electronicinvestigations1253 10 ปีที่แล้ว +7

    Thanks Dave, keep up the Fundamentals videos. I can't wait to get out to my lab and try this with my own scope..

  • @ronmuller9899
    @ronmuller9899 10 ปีที่แล้ว +1

    Excellent video. Instrumentation and measurement and understanding the limits of your equipment and sources of errors are very important and often a poorly understood area. Nothing like a real demonstration to highlight the concepts and pitfalls. Good stuff Dave.

  • @Fractal80Y
    @Fractal80Y 10 ปีที่แล้ว +25

    Wonder if you could do a video on ground loops? Thanks great channel!

    • @HighestRank
      @HighestRank 3 ปีที่แล้ว

      th-cam.com/video/wopmEyZKnYo/w-d-xo.html

  • @INCYTER
    @INCYTER 2 ปีที่แล้ว +2

    Dave, I really like your channel. Outstanding quality topics, content, judgement and sharing of your understanding and tricks. Thank you for sharing your excellence and passion.

  • @exce51
    @exce51 10 ปีที่แล้ว +6

    Thanks for doing the fundamentals. These are my favorite videos.

  • @BradMorrisKA3YAN
    @BradMorrisKA3YAN 10 ปีที่แล้ว +1

    I've been wondering for months what a CRO probe was. True, I didn't look it up, but still wondered. Cathode Ray Oscilloscope (CRO) probe.
    Brilliant!

  • @roboknight
    @roboknight 9 ปีที่แล้ว +1

    Dave, really awesome. Well worth the time. Thanks for going through this one. I can't tell you how much the EEVBlog comes up here at work lately. Too many geeks with not enough to do? ;) ... Love it.

  • @AllElectronicsGr
    @AllElectronicsGr 10 ปีที่แล้ว +24

    Why the 50ohm terminators made so much diference?

    • @Flapjackbatter
      @Flapjackbatter 10 ปีที่แล้ว +8

      Yes Mr Johns. Make a short video explaning about 50 ohm termination. Pliiiiiizzzz , with sugar on . Please ?

    • @aptsys
      @aptsys 10 ปีที่แล้ว +5

      In this example it gave the signals a reference since the PSU is a floating supply.

    • @DantalionNl
      @DantalionNl 10 ปีที่แล้ว +4

      It also acted as a voltage divider because the probes have about 300 ohms of resistance

    • @FrozenHaxor
      @FrozenHaxor 10 ปีที่แล้ว +3

      Because without it the PSU output is at a high impedance.

    • @atexnik
      @atexnik 3 ปีที่แล้ว +2

      It has to do with the coax usually having 50 Om impedance as well. Basically, the coax is a tramission line, and when you trasmit a signal over coax, it is vitally important to have it terminated with a matching impedance load. Otherwise, you get the signal all messed up.

  • @discoHR
    @discoHR 8 ปีที่แล้ว +3

    Measuring the ripple is so much easier using a True RMS multimeter. Set it to AC voltage, read the result, done. However, using a scope is more fun.

  • @Ronb008
    @Ronb008 9 ปีที่แล้ว

    It's everyday friday here! thanks Dave for your lessons!

  • @nathanas64
    @nathanas64 5 ปีที่แล้ว +1

    Great lectures. Definitely talented instructor.
    But how do you get rid of noise??

  • @stevenhardy2898
    @stevenhardy2898 9 ปีที่แล้ว +2

    There is another aspect of power supply noise that is little thought of. I was involved with a huge project at a large computer site in 2010 that had to have the power supplies replaced on 5000 installed servers. The switching power supplies also generate noise back onto the ac feed line. When you had 5000 servers with no isolation, all generating noise, the electrical noice would shut down the site UPS systems. The replacement power supplies,all 10,000 of them fresh in from China,now had toroid coils on the ac line. Guess the server vendor didn't save 20 cents per server after all ?

  • @JohnSmith-iu8cj
    @JohnSmith-iu8cj 4 ปีที่แล้ว

    You, Sir, are a gift from heaven!

  • @larrypridgen4785
    @larrypridgen4785 8 ปีที่แล้ว +6

    Hey Dave, where can you buy the probe BNC adaptor for the rigol scope. Do you have a part number. Cheers

  • @vianacode
    @vianacode ปีที่แล้ว

    Awesome explanation of all the concepts!

  • @aliens1192
    @aliens1192 2 ปีที่แล้ว

    An awesome video that I have been watching since years again and again! Thanks Dave! :)

  • @andrealves7938
    @andrealves7938 8 ปีที่แล้ว +1

    Those measurement tips and tricks were sooooooooooooo informative. Thanks for sharing this content!

  • @Switching-powerBlogspot
    @Switching-powerBlogspot 10 ปีที่แล้ว +1

    Excellent because it shows the tips&tricks of ripple and noise measurement.

  • @ambassadorkees
    @ambassadorkees ปีที่แล้ว

    That HP calculator induced memories. Highschool programming, iterating math & stuff.

  • @richwiskin4860
    @richwiskin4860 ปีที่แล้ว

    Brilliant video. So useful. Perhaps I shouldn't be so disappointed with my digital scope after all! Thank you.

  • @jasonhensley489
    @jasonhensley489 9 ปีที่แล้ว +2

    Thank you, thank you, thank you! Starting out in electronics and your video's help so much!

  • @quarkhirad
    @quarkhirad 3 ปีที่แล้ว

    Hey nice video. Though one more way to get rid of high frequency noise is to use a 0.1 micro farad disc cap on the probe tip. Infact you can solder it onto the probe tip and then leave a little bit of lead say 3mm extra to act as the points to probe the power supply. This is one of the standard methods

  • @oriole8789
    @oriole8789 10 ปีที่แล้ว

    I got some Lambda LQ/LQD series linear bench PSUs recently, circa 1983 (warranty seals were unbroken haha!).. their ripple + noise specs are 0.15mV RMS, 1mV pkpk. Temp coeff. is ±(0.005% + 10μV) /°C. Line/load regulation is 0.005% + 0.5mV. Current regulation is 1mA/2.5mA (line/load), at full voltage range. Just fantastic. I verified those figures with my scope, still fully within specs. Zero overshoot with maximum load. They employ a custom Lambda branded IC for V/I regulation. I've sourced a replacement for one from China, gonna see if the specs change after I put it in.. I suspect it's not an original part from 31 years ago. :P

  • @tubical71
    @tubical71 10 ปีที่แล้ว +1

    I got a whole lecture on noise and distortion when i studied EE, we did a huge amount of mathematical theory and a lot of fourier transform, 3rd order interseption points and stuff like that back than, but we did *not* measure a thing even at the coresponding laboratory lecture...sad...sad.

  • @OrbiterElectronics
    @OrbiterElectronics 10 ปีที่แล้ว +9

    Great vid Dave. Thanks

  • @bcsupport
    @bcsupport 10 ปีที่แล้ว

    Dave Jones, the EE Professor

  • @markuscwatson
    @markuscwatson 5 ปีที่แล้ว

    I miss Dave's videos like this

  • @tubical71
    @tubical71 10 ปีที่แล้ว +1

    Another trap for a "young-player" might be that when one is playing around with the scobe probes and a power-supply, and they are both grounded via earth (3-pin mains) it may set the mains/installation fuse off or the "FI-switch" or both may in addition to a defective scope or PS. That´s why i´m running my scopes over a isolation transformer, in my case a 230V/230V to power up the scope. The tranny decouple its 230V output from earth.

    • @f7497
      @f7497 10 ปีที่แล้ว +2

      I've also isolated my scope. Solved a lot of my mains noise problems.

  • @Chris-ut6eq
    @Chris-ut6eq ปีที่แล้ว

    Fundamentals Friday FTW!

  • @caseyrevoir
    @caseyrevoir ปีที่แล้ว +1

    That was heavy (but fun). I have found if an auditing Piezo sounds 'normal', were golden. If the screech is too Bjork or Yoko then I find a Dave.

  • @PeterCCamilleri
    @PeterCCamilleri 10 ปีที่แล้ว +2

    Excellent, informative, and eye and mind opening!!! Thank You!!!

  • @bertblankenstein3738
    @bertblankenstein3738 ปีที่แล้ว

    There is a lot of good info here. I got that exact ds2202 and I'll have to check some of the linear PS i have. I will certainly learn something, most likely the probing. Great video.

  • @gamccoy
    @gamccoy 10 ปีที่แล้ว

    Terrific video, Dave. I went into this thinking I would not learn a thing. I was wrong.

  • @jonathanseyfert8256
    @jonathanseyfert8256 8 ปีที่แล้ว +4

    I had to laugh. He measures 20 mV pk-pk, and he says it's garbage. I just got my first O-scope running and measuring a cheap SMPS, a Chinese 13.8 V, 25 A power supply made for powering RC battery chargers. I get 1 V pk-pk ringing at 62 kHz, and adding about 10 A load I now get an almost 2 V pk-pk ringing 5 µs in front of the 1 V pk-pk ringing. From looking at the trace under load, the bigger ringing appears to be the supply switching "on" and the smaller ringing the supply switching "off".
    Anyhow, THAT is a garbage signal. Fun stuff. Works great powering simple 12 V loads like lights or battery chargers though.

  • @whiskeyify
    @whiskeyify 10 ปีที่แล้ว

    good video, I didn't understand it all, I'm a repair tech not an engineer, but I did learn a lot. thx Dave

  • @quarkhirad
    @quarkhirad 4 ปีที่แล้ว

    hi nice video dave. Though in my company which made power supply for defense institutions and special custom built power supply. The way we would measure ripple is to use a single probe but solder a 104 disc cap on the tip ( 0.1 micro farad) on the tip. off course no use the ground lead that is serious a big ******* antenna.

  • @Mtaalas
    @Mtaalas 10 ปีที่แล้ว +3

    Wohoo! :D
    I have waited for these videos :)
    Thanks Dave!

  • @BenBilesBB-box
    @BenBilesBB-box 8 ปีที่แล้ว

    great video ! helped me a lot. got here because of exactly the kind of spikes seen in this video from a dual rail power supply i built.

  • @yaghiyahbrenner8902
    @yaghiyahbrenner8902 10 ปีที่แล้ว +2

    hey, that brick converter you used is used as a 5v / 2A BEC for quadcopters.Differential probes are shit expensive :(

    • @EEVblog
      @EEVblog  10 ปีที่แล้ว +6

      Yep, they can cost more than your scope.

  • @AlexBenfica
    @AlexBenfica 8 ปีที่แล้ว +1

    Amazing video! Learning a lot... much more than at school!

  • @Oshbotscom
    @Oshbotscom 10 ปีที่แล้ว

    How do we talk you into doing more Fundamental Fridays? I absolutely love these segments.

    • @ionyou
      @ionyou 10 ปีที่แล้ว

      "How do we talk you into doing more Fundamental Fridays?"
      Make more Fridays. TGIF. If everyone thanks god for Fridays, how come there's only 1 Friday per week?

    • @Oshbotscom
      @Oshbotscom 10 ปีที่แล้ว

      ionyou I wasn't aware that Dave put out a "Fundamentals Friday" video every Friday. When did this happen?

  • @yishujia186
    @yishujia186 10 ปีที่แล้ว +1

    Hi, I haven't gone through all your videos. But I wish you could make some videos on different kinds of sensors and motors or even robotics control. That would be an interesting topic.

  • @paulg.3067
    @paulg.3067 5 ปีที่แล้ว

    I dont understand 24:04 when he adds the "50Ohms Terminators"... I only know terminators that act as an end cap, but he uses obliviously something else ? His terminators have in- and outputs??? I am confused.

  • @permitivitym4318
    @permitivitym4318 10 ปีที่แล้ว

    nice video. it would be interesting if you discuss about power supply transient response as well in your next video

  • @FooBar89
    @FooBar89 6 ปีที่แล้ว

    you don't need 400uV vertical sensitivity, you need a good pre-amplifier, and you can measure down to microvolts; that's how Linear does it

  • @bozoc2572
    @bozoc2572 6 ปีที่แล้ว +1

    Really insightful. Thank you Dave!

  • @SetMyLife
    @SetMyLife 10 ปีที่แล้ว

    Very helpful Dave, just what I need right now!

  • @TheModelmaker123
    @TheModelmaker123 10 ปีที่แล้ว

    I was hoping you would test the power supply you designed to see how it compares to the Rigol.

  • @mikefinn2101
    @mikefinn2101 ปีที่แล้ว

    Great explanation well done

  • @petersage5157
    @petersage5157 6 ปีที่แล้ว

    16:50 ....but...but "digital scopes are just better!" LOLing at your DSO vs CRO videos. The testing equipment manufacturers really took a step back when they abandoned analog scopes; measuring noise was a big part of a CRO's bread & butter.

    • @EEVblog
      @EEVblog  6 ปีที่แล้ว

      Wrong. I've done a video on analogue vs digital scope noise if you want to educate yourself

    • @petersage5157
      @petersage5157 6 ปีที่แล้ว +1

      You've done two; I've watched both of them a couple of times. Your claim in the second one that "they're just better" (referring to digital scopes) at showing and analyzing noise is refuted by your comments at the time index referenced in my previous post here. A two-channel CRO does the business with just throwing a couple switches; with a DSO you need to use three channels, adjust persistence and muck around with channel phase inversion and, in some cases, buy (or hack) a software option for an analysis package.
      You do concede in the first analog vs digital scope video (and in all your $50 eBay scope videos) that every EE should have an analog scope as entry-level gear, which goes to the point of my previous post: given their utility, there's no good reason not to still make oscilloscopes that are analog from the front end to just in front of the display driver, with no digital storage or software analysis (today's and tomorrow's EEs still know how to use a calculator, right?) Translating CRT beam deflection for an LCD driver should be trivial.
      ...which gives me an idea, so thank you for challenging me on this. A true analog scope with an LCD might be a cool open-source project. Most of the CRO designs came out of patent a long time ago.

  • @Nikkuuu69
    @Nikkuuu69 10 ปีที่แล้ว +12

    Hey Dave! Thanks for this amazing, content filled video! I has one question, what do the 50 ohm terminators do exactly?

  • @makingtolearn
    @makingtolearn 7 ปีที่แล้ว

    Found this to be enormously helpful- thanks!!

  • @meowcula
    @meowcula 10 ปีที่แล้ว

    Hugely instructive as usual Dave! Cheers!

  • @Kd8OUR
    @Kd8OUR 10 ปีที่แล้ว

    These videos are great. You would have a blast at the Dayton Hamvention.

  • @PuchMaxi
    @PuchMaxi 10 ปีที่แล้ว

    This is exactly what I needed, thanks for explaining Dave!

  • @shiweiluan
    @shiweiluan 8 ปีที่แล้ว

    Hi Pro, at 14:37, could you explain why the ground wire of probe picks up noise? Thank you.

    • @AdamCchannel
      @AdamCchannel 8 ปีที่แล้ว

      +Shiwei Luan The ground wire forms an inductor coil and the noise it picks up is some electromagnetic interference generated by other devices in the room - in this case mostly PWM-controlled LED lights.

  • @TheBadFred
    @TheBadFred 10 ปีที่แล้ว

    You should try the noise testing with an old DECT phone next to it.

  • @henryrey1840
    @henryrey1840 6 ปีที่แล้ว

    Something I notice is that using buck converters that let me regulate current, such as battery chargers (XL4015), I had way more noise when I demanded a current near to the limit I put on. Lets say I set my power supply to deliver up to 1.2A, when I put a load that demanded 1A y had some noise, but if I limit the current up to 2A with the same load, at the same conditions, the noise was smaller than before ._.

  • @pepe6666
    @pepe6666 7 ปีที่แล้ว

    spectrum analyser is a great way to see what noise looks like. since i am poor i use my audio interface with software doing fourier transform. can see all the harmonic lovelies

  • @alejandrovaistij632
    @alejandrovaistij632 7 ปีที่แล้ว

    Dave, excellent tutorials, can you explain how to measure the any oscilloscope noise floor ?

  • @gamerxp01
    @gamerxp01 9 ปีที่แล้ว

    Follow up this video from Afrotechmods 's DC-DC Buck Converter. And keep following up Dave and your videos are awesome! I can learn EE start just my a little knowledge of EE in high school (in Thailand) to starting some basic of Reverse Engineering! Well you're rock, Dave.

  • @vhm14u2c
    @vhm14u2c 5 ปีที่แล้ว

    Thanks for sharing, Dave

  • @Dms57
    @Dms57 7 ปีที่แล้ว +1

    Hi Dave,
    Can't you set the oscilloscope in 1MOhm resistance and measure it using two probe technique, without attenuation?

  • @00Skyfox
    @00Skyfox 8 ปีที่แล้ว

    Dave used a 50 ohm terminator on the oscilloscope. What is a 50 ohm terminator and what are they used for? I need my fundamental Fridays to be even more fundamental.

    • @AdamCchannel
      @AdamCchannel 8 ปีที่แล้ว

      +00Skyfox Read about "transmission line termination" to really understand it. In short - a terminator is simply a resistor that prevents signal from reflecting at the end of the transmission line back to the signal source which would interfere with your measurement. BTW, not all scopes have a built-in terminator.

  • @pepe6666
    @pepe6666 8 ปีที่แล้ว

    this was amazingly informative. another ripper dave this has been really useful. great scientific reasoning

  • @aneeshprasobhan
    @aneeshprasobhan 4 ปีที่แล้ว

    For the past month, i have been taking hundreds of measurements the wrong way for my university project. Even the professors or the research assistants didn't tell me any of this. How I wish I saw this video one month earlier. 😭😭😭

    • @seinfan9
      @seinfan9 4 ปีที่แล้ว +1

      Well, most don't do much of any hands on work. They get their grunt TAs lead all the testing, and even then, the TAs will rely on a lab technician with the electronics know how like Dave here.There are a few professors that do lab work, don't get me wrong. But most academics are snobs that won't bother with the dirty tedious work of testing and debug. Most electrical engineers just plain never learn this stuff because most of the EE jobs out there don't have an emphasis on this kind of testing. You see plenty of digital design, fpga and software coding positions, but they don't get exposed to dealing with these front end realities.

  • @dinkc64
    @dinkc64 10 ปีที่แล้ว

    Another great video, thanks Dave!

  • @suppersreadysuppers1822
    @suppersreadysuppers1822 10 ปีที่แล้ว +1

    Many thanks Dave

  • @tablatronix
    @tablatronix 7 ปีที่แล้ว +1

    Can you measure this using a bench DMM using maths or AC setup ? That would be a useful video. Is it really as easy as RMS AC ?

  • @aircooledcamper
    @aircooledcamper 9 ปีที่แล้ว +1

    Why the series 50 ohm resistances at the far end of the differential measurement coax in additon to the parallel 50 ohm? Edit: Nevermind, I see the low impedance power supply needs a series resistor on its end to match the coax. Great video, by the way. I learned a lot. Thanks, Dave.

    • @vonnikon
      @vonnikon 3 ปีที่แล้ว

      No, your original question is valid.
      There is no need for the source resistors. They will just add undesired attenuation.

    • @robegatt
      @robegatt 3 วันที่ผ่านมา

      ​@@vonnikonnope, it's a transmission line

    • @vonnikon
      @vonnikon 3 วันที่ผ่านมา

      @@robegatt there is no need for the source impedance to match the characteristic impedance of a unidirectional transmission line.
      The source impedance only represents energy loss in this scenario.
      Bidorectional transmission line is another story. There you need to also match the source impedance.

    • @robegatt
      @robegatt 3 วันที่ผ่านมา

      @@vonnikon there is nothing like "uniderctional transmission line" ! If the source impedance is missing you have the signal bouncing back at the source right at the beginning of the line.

    • @vonnikon
      @vonnikon 3 วันที่ผ่านมา

      @robegatt try it!
      It works perfectly fine.
      Plenty of transmission lines use a low source impedance. 10/100MBit Ethernet to name a popular example.

  • @Ronaldvester
    @Ronaldvester 10 ปีที่แล้ว

    Woo Dave 666 videos on your main channel!
    Keep up the great work!

  • @Impedancenetwork
    @Impedancenetwork 7 ปีที่แล้ว

    Wow! That was low tech but for me that was very interesting. I have that same Rigol scope and power supply. I also have that DC programmable load. I had no idea that load could put that noise on the there. Very interesting. I know my equipment a lot better now. Thumbs up!

  • @SuperJetjockey
    @SuperJetjockey 9 ปีที่แล้ว

    Absolutely excellent tutorial. I am going to have to troubleshoot the power supply of my VTVM, and my thinking is to make the probes you demonstrated for my Tek 475 scope. I have another option that I wanted to ask you about, however. It happens that I have an old Tek 545b scope with a differential plug-in. My question is, what is the best way to hook it to the power supply, or am I just as well off to use your adaptors and the later model 475 scope.
    Thanks,
    Bob

  • @apprenticemart2
    @apprenticemart2 10 ปีที่แล้ว

    Love the tuts Dave.

  • @foxyrollouts
    @foxyrollouts 8 ปีที่แล้ว

    You make a good lecturer

  • @zynthos9
    @zynthos9 5 ปีที่แล้ว

    Why would using two separate probes in subtract mode reject common mode noise whereas s single ened connection would not?
    Single ended connection still takes difference between signal and ground so if noise is common to both, it should cancel out right?

  • @kubockferre5532
    @kubockferre5532 5 หลายเดือนก่อน

    hi i got a tecktronix analog with ac coupling on that ,can i measure 450v dc supply with 1 x probe or i must use 10 x probe ,can i see ripple on my scope with 10 x probe .What value is acceptable for ripple!thanks

  • @DjResR
    @DjResR 10 ปีที่แล้ว

    It was quite educative video, thanks for sharing. I wonder what is the noise level in 20+ years old computer power supply?

    • @kyoudaiken
      @kyoudaiken 10 ปีที่แล้ว

      I think it is not much worse than today ones. Back then ripple was also a problem. Current PSUs are only much more efficient than the old ones. And the caps are of course crap, because they wanna save the last bottom microcent.

  • @tanner1985
    @tanner1985 4 ปีที่แล้ว

    Top notch and informative video, thanks

  • @filjka
    @filjka 4 ปีที่แล้ว

    Hey. Why you do not suggest to disconnect probes from power supply to check if noise is picked up by probes themselves?

  • @eddyane67
    @eddyane67 6 ปีที่แล้ว

    Great Dave! I have learned a lot with this video. Thanks

  • @fiveleafcloverfpv4445
    @fiveleafcloverfpv4445 ปีที่แล้ว

    Hi Dave,
    Al video but can't find the information I need.
    I need to measure some powersuppy noise. (cheap or RC equipment)
    Yoi made the probes at 32min.
    I think this will do but do you have a tutorial or pictures from this how you made it.
    Type of coax (impedance) . Resistor and the capacitor you used?
    Mabve buying a BNC cable
    Cutting it in 2 pieces to start with.
    Thank you in advance or any follower that replies.

  • @Pixilshooter
    @Pixilshooter 10 ปีที่แล้ว +1

    Please explain why you have the oscilloskop on AC coupling when measuring a DC signal..?

    • @simonfitch1120
      @simonfitch1120 10 ปีที่แล้ว +2

      He wasn't measuring DC, he was measuring noise and ripple, which are both AC components riding on the DC. 5V DC would have over-driven the scope on the mV ranges, and so AC coupling was needed to bring the signals back down to 0V average.

    • @Michalmas64
      @Michalmas64 10 ปีที่แล้ว

      Ripple and noise, are AC signals...

    • @EEVblog
      @EEVblog  10 ปีที่แล้ว +3

      Because you can't measure the small amplitude AC signals in the presence of a larger DC voltage. The ADC in the scope doesn't have the resolution. e.g. a 5V DC supply and 8 bit ADC gives you 19.5mV per bit. So 20mV noise will only appear as 1 bit flipping on an off - useless.
      Same for the analog scope where you won't be able to see the small noise on the DC signal

    • @Pixilshooter
      @Pixilshooter 10 ปีที่แล้ว +1

      Thanks for the comments guys. I find it all very interesting even though I sometimes don't understand everything.

    • @gordonhayslip9403
      @gordonhayslip9403 7 ปีที่แล้ว

      EEVblog i

  • @gglovato
    @gglovato 10 ปีที่แล้ว +1

    is there a way you can shield the PS for your lights with proper grounding?, the ammount of RF noise that thing is putting out is insane!

    • @kyoudaiken
      @kyoudaiken 10 ปีที่แล้ว +1

      I also have LED retrofit T9 tubes here. 6 of them in my living room 6500K. I'm not able to recieve FM radio anymore, when I have them on, altough the lamp fittings are grounded and even the reflectors are grounded. Problem is that the tubes are lacking of input common mode choke and filtering. The LIVE and NEUTRAL wires are acting as big chunky antennas... I think it's time to make coaxial mains cables, because of cheap thinking china products... And the tubes were quite expencive and the overall quality is very good. It seems just lacking the input filtering... Too much copper wire for the choke and additional inducter plus some caps...

    • @gglovato
      @gglovato 10 ปีที่แล้ว

      *****
      then put a filter in the input and let us know, you can get one of those filter modules that PSUs use from old PSUs (some of them have IEC C14 receptacle integrated) or just use the filtering board from a computer PSU as well

    • @kyoudaiken
      @kyoudaiken 10 ปีที่แล้ว

      I have some filter circuits from the formery electronic ballasts of these fittings. But the circuit does not fit into the tubes, nor does it fit into the fitting anymore... :/

  • @SabretoothBarnacle
    @SabretoothBarnacle 10 ปีที่แล้ว

    Any recommendations for the Caps on the Homebrew probes? Will just a small value ceramic do the job??

  • @SpacePunk1000
    @SpacePunk1000 9 ปีที่แล้ว

    what would be an appropriate test setup, to see if the noise is making it onto the output of my rf amplifier? Spec An? Oscope?

  • @HardlineFeminists
    @HardlineFeminists 10 ปีที่แล้ว +1

    Where can I buy a ripple suppressor for my LED power supply? I'm getting a strange strobe effect on certain outlets, but I don't want to have to buy another regulated power supply. Anyone know?

    • @SebastianScholle
      @SebastianScholle 7 ปีที่แล้ว

      Try a ferrite bead. They are designed to lower supply ripple

  • @tonidejaumarvilas121
    @tonidejaumarvilas121 6 ปีที่แล้ว

    Great great video Dave!!!! Many thanks!!!

  • @wilvanlierop
    @wilvanlierop 10 ปีที่แล้ว

    I really liked this one! Thumbs up and more of this please.

  • @emremutlu44
    @emremutlu44 9 ปีที่แล้ว

    But, what about making an inst. amp. design to use with measuring diff. values ? Maybe you can sketch a design with specific parts for us to have it use on our scopes... Please :)

  • @HellTriX
    @HellTriX 10 ปีที่แล้ว

    How do I know if my ripple capacitors can handle the ripple current? I have some surplus caps that I am using for ripple suppression, they are rather large and I am scared they will blow up if I have too much ripple current. It's on a 110vAC 60hz input with rectified ripple of 4-6v p/p. The Current load is 150amp for a DC motor load. Caps are 250v 2000uF each but that's about all the specs I have on them.

  • @stevenbliss989
    @stevenbliss989 6 หลายเดือนก่อน

    I wonder if there is any digital scope that can do diff IN ANALOG HARDWARAE like analog scopes do?

  • @LarsBerntzon
    @LarsBerntzon 10 ปีที่แล้ว

    Im also thinking about the 50 terminators, why did that change the situation as much? I mean the shield was already grounded so the core should not pick up so much noise, right?

    • @tubical71
      @tubical71 10 ปีที่แล้ว

      It is not only shielding, is also about impedance. If your ground is of "high" impedance ther will be a voltage drop. If your signal leed had an intrinsic impedance you´ll "only" get a voltage divider. If you have a ground impedance in your wire it is the same but little more: It is a voltage divider as well as an antenna for all kinds of fields. Magnetic and electric as well.