How much its important to not buy 50Mhz scope - Page 1
Forum section: electronics / beginners

author: sairfan1
author_rank: Frequent Contributor
timestamp: February 24, 2021, 02:24:25 am
content: I was planning to buy Rigol DS1054 or Rigol DS1104 price difference is significant that's why i was planning to buy 1054 i want to know how much its important to go for 1104 like what im going to lose.I mostly work on uC ESP, PIC, and will be looking for like from sleep to read data from sensor and go sleep timing for such scenario,capacitor charge/discharge, triggers, switching transistor etc.

author: ejeffrey
author_rank: Super Contributor
timestamp: February 24, 2021, 04:43:06 am
content: 100 MHz isn't some kind of magic number. For most microcontroller projects a 50 MHz scope will work just fine. If the cost difference gives you pause, I would definitely say go for the 50 and save your $$ for other equipment or parts and PCBs. And as blueskull says, you can crack the scope to higher bandwidth anyway.

author: rstofer
author_rank: Super Contributor
timestamp: February 24, 2021, 11:58:38 am
content: This question is asked, in varying forms, about every week. The answers don't change much.Here's a very long thread that covers a range of topics related to selecting, and using, an oscilloscope. It will take some time to read since Charlotte doesn't actually buy a scope until Reply 150 or so. The real fun starts when she begins experimenting with every possible thing the scope can do. It's well worth the read. Who knew a scope could do mathematical integration?https://www.eevblog.com/forum/beginners/what-an-oscilloscope-recommended-for-a-woman-passionate-about-electronics/msg3100087/#msg3100087The fundamental decisions are: 2 channels versus 4 channels, 100 MHz versus 200 MHz, Rigol DS1054Z versus Siglent 1104X-E, Siglent 1102X-E, Siglent 1204X-E. Obviously, the Rigol needs to be unlocked to move it from 50 MHz to 100 MHz but that's pretty easy and proven to work.Somewhere in that thread there will be a discussion of the Fourier Series representation of a square wave. In a nutshell, a 100 MHz scope will do a decent job of displaying a 10 MHz square wave and a lousy job with a 100 MHz square wave. Indeed, it will look like a sine wave with no square attributes at all. So, after spending money on a 100 MHz scope, don't expect to display high frequency square waves. Obviously, a 50 MHz scope won't do a decent job much over 5 MHz.In this animation, you can see a square wave composed of the 1st, 3rd, 5th and 7th harmonic. Take 100 MHz and divide by 7 and the highest frequency you could faithfully display is around 14 MHz.https://gist.github.com/amroamroamro/617305c05001caffc8d0You can see how the corners are rounded and this is because we need more harmonics to square the waveform. I realize this explanation is over the top but it's important to understand that the scope will reproduce a 100 MHz sine wave, not a 100 MHz square wave.In terms of most hobbyists, a 100 MHz scope is adequate, 200 MHz would obviously be preferred.Then there is the issue of channels. I wanted 4 channels so I could decode the SPI protocol on uC projects. Charlotte traded more bandwidth and only 2 channels. It's a tradeoff.Good luck!

author: rstofer
author_rank: Super Contributor
timestamp: February 24, 2021, 12:10:21 pm
content: Shorter answer with no math: Today I would buy the Siglent SDS1104X-E and unlock it for 200 MHz. I want 4 channels above all else but the higher bandwidth would be useful for FPGA projects. When I bought the Rigol DS1054Z, the Siglents weren't available. There is nothing wrong with the DS1054Z and there is a VERY LONG thread about the scope over in the Test Equipment forum. The problem with that thread is separating out the complaints that have been resolved with firmware upgrades over the last few years. It might be worth skipping to the last few pages...I can buy the Siglent SDS1104X-E for $499 or the Rigol DS1054Z for $349. I could then unlock the Siglent for 200 MHz and the Rigol for 100 MHz. Is that extra bandwidth worth $150? In my view yes. Then again, the Rigol is working fine!

author: sairfan1
author_rank: Frequent Contributor
timestamp: February 24, 2021, 05:18:11 pm
content: How do you compare Siglent with Rigol, is it as good as Rigol? like if we compare 1104X-E with 1104-Z plus (or may be Z-S which ever are closer models) do we have comparable functionality and performance?I also want to know why are those logic analyzer probs are so expensive almost at cost of a scope, does not make sense to me.

author: bdunham7
author_rank: Super Contributor
timestamp: February 24, 2021, 05:29:47 pm
content: Quote from: sairfan1 on February 24, 2021, 05:18:11 pmI've had both, they both work but the Siglent is significantly better for reasons that have been hashed to death already in this forum. The Siglent 1104X-U and the Rigol DS1054Z are comparable (after hacking) and the Siglent costs a bit more, as would be expected. However, the 1104X-U is just a slightly stripped version of the 1104X-E and unless your budge is very tight, I don't think the cost savings justifies geting the cheaper one. I would try to score an 1104X-E on sale, they were recently $449USD on Amazon here.As for the LA probes, what can one say--they're a bit complicated to make, I suppose. I don't think they are a popular option and I've never seen one in use.

author: rstofer
author_rank: Super Contributor
timestamp: February 24, 2021, 06:43:21 pm
content: Now you need to find actual reviews for the various models of interest. How do you know which models to consider? Read the User Manuals and build up a spreadsheet of features and capabilities. It's a very long process and it's more difficult with Siglent cluttering up the space with nearly identical scopes.I don't have the feature on my Rigol but I would certainly not want to give it up to change from X-E to X-U - the Bode' plot. Mind you, I have never done this on a scope and it takes a compatible signal generator (which I have - SDG2082X). I don't think I would ever actually use the feature on a scope since the Analog Discovery does a much better job but I'm not sure that I would want to give it up just to buy the X-U version.In general terms, the Siglent is purported to have a much nicer user interface than the Rigol in terms of being responsive to knob twiddling.You can hit up Google for reviews. Many of the replies will point back to eevBlog. Charlotte is the only person I have ever heard of who wanted to test every single feature of her scope. That's why I posted that link.One problem might be feature overload. The modern DSO does so much that it takes a careful review to see if a) the feature is implemented correctly and b) whether it even needs to exist.Or, sort the scopes I listed earlier by price and pick a point. The Siglent SDS1104X-E unlocked to 200 MHz would be my choice but there's certainly nothing wrong with the Rigol DS1054Z unlocked to 100 MHz. I wouldn't be interested in a 2 channel scope but the Siglent SDS1202X-E is a good choice.While searching the Test Equipment forum, look for the threads that discuss "issues" and see if they have been fixed in later firmware. All known bugs are out of the Rigol but I haven't been following along for the Siglents. Rigol has been very responsive with firmware updates.

author: tggzzz
author_rank: Super Contributor
timestamp: February 24, 2021, 07:04:47 pm
content: Quote from: rstofer on February 24, 2021, 11:58:38 amAnd then there will be the usual response that the frequency/period is irrelevant for digital signals - the only parameter that matters is the risetime.A 100MHz scope will have risetime of 3.5ns.Do have a look at Charlotte's thread!

author: rstofer
author_rank: Super Contributor
timestamp: February 24, 2021, 07:34:17 pm
content: Dave did a video about MSO scopes. Although he likes MSOs, he doesn't recommend upgrading the DS1074. For most hobby purposes, the 8$ AliExpress logic analyzers will be adequate. The lack of a state clock input for MSOs is pretty much fatal.https://youtu.be/MC9_4mpqVgUSee 10:25 ...Personally, I built up a 32 channel LA with an FPGA board because I needed a lot of channels but, again, for most uC projects, that isn't necessary.Although hard to get, the Digilent Analog Discovery has 16 digital inputs that can be used as a logic analyzer or there is the Digital Discoveryhttps://store.digilentinc.com/digital-discovery-portable-usb-logic-analyzer-and-digital-pattern-generator/I am a huge fan of both of these devices. I liked the Analog Discovery 2 at the old price of $279 a lot more than at the new and improved price of $399. They have been out of stock since the Covid thing started because EE students are using them instead of going to a more formal school lab.For 'learning' electronics, the AD2 is a much better choice, financially, than buying the equivalent tools. I use mine in preference to my scopes and signal generator. Not that it matters to me but, if I were a student, I would have one of these in my backpack along with my laptop. A truly portable lab.Anyway, skip the MSO bit...

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: February 24, 2021, 08:27:20 pm
content: I have a rigol DS1054z released at 100Mhz,for my Arduino projects, micro-controllers and electronics, it works very well,- the interface is slow, but it is not a serious problem- I would have liked it to decode in memory and not just the screen. (option to buy a dslogic plus)-But if it annoys me a lot is that the Rigol Engineers do not release a patch for the error in some measurements when the 24 bit depth is selected.PS: Use for hobby and small jobs to third partiesin spanishyo poseo un rigol DS1054z liberado a 100Mhz,para mis proyectos de Arduino, microcrontroladores y electronica, funciona muy bien,- la interfaz es lenta, pero no es un problema serio- me hubiera gustado que decodifique en la memoria y no solo lo de la pantalla.(opcion comprar un dslogic plus)-Pero si me enoja mucho es que los Ingenieros de Rigol no lanzen un parche para el error en algunas mediciones cuando se selecciona los 24 bit de profundidad.PD: Uso para hobby y pequeños trabajos a terceros

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: February 24, 2021, 11:43:53 pm
content: Quote from: Adrian_Arg. on February 24, 2021, 08:27:20 pmI'm sure Rigol would be equally annoyed you hacked their product. Are the errors a result of using a device beyond its specification?

author: sairfan1
author_rank: Frequent Contributor
timestamp: February 25, 2021, 03:16:39 pm
content: I'm also more thinking about Siglent 1104X-E i was looking at there pagehttps://siglentna.com/product/sds1104x-e-100-mhz/Looks like $499 is not the final price i will have add lots of thing separately like wifi and logic analyzer related that will bring the price up again to rigol 1104z-s

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: February 25, 2021, 04:20:07 pm
content: Quote from: sairfan1 on February 25, 2021, 03:16:39 pmthe measurement error in the 24 bit depth scale, also those who bought the DS1054Z that are already unlocked and did not modify the 50 Mhz to 100 Mhz have it. in my case, I bought it in tequipament USA, they gave me a daughter-in-law to register with Rigol to obtain the 100 Mhz license. Also, if you report that problem, the DS1000Z models seem to have them.in spanishel error de medicion en la escala de 24 bit de prundidad, tambien lo tienen aquellos que compraron el DS1054Z que ya vienen desbloqueado y no modificaon los 50 Mhz a 100 Mhz. en mi caso yo lo compre en tequipament USA, me otorgaron un nuero para registrarme en Rigol para obtener las licencia a ecepcion de los 100 Mhz. Ademas si te informas ese problema parece tenerlos los modelos DS1000Z.

author: rstofer
author_rank: Super Contributor
timestamp: February 25, 2021, 05:31:19 pm
content: Quote from: sairfan1 on February 25, 2021, 03:16:39 pmYou need to wander over to the Test Equipment forum and search for 'unlock siglent sds1104x-e'See reply 103 here:https://www.eevblog.com/forum/testgear/unlocking-siglent-sds1104x-e-step-by-step/100/Of the 3 items on the Siglent page, none are required. The AWGs are external boxes, the MSO is probably not worth the cost and the WiFi may not be necessary. If it is, figure to pay for the firmware. Hopefully any dongle would work but I might buy the Siglent recommended version anyway.Here is Dave's take on the MSO option:https://youtu.be/MC9_4mpqVgU?list=UL0UksWKuVFFoOther than cost, there's no reason not to just buy the 200 MHz version.

author: rstofer
author_rank: Super Contributor
timestamp: February 25, 2021, 05:33:48 pm
content: Quote from: sairfan1 on February 25, 2021, 03:16:39 pmBut the Siglent can be unlocked for 200 MHz, the Rigol is maxed out at 100 MHz.

author: sairfan1
author_rank: Frequent Contributor
timestamp: February 26, 2021, 02:40:53 am
content: BTW what is difference between Rigol 1104Z and 1104Z plusHere is a video comparing rigol with signent

author: JustMeHere
author_rank: Frequent Contributor
timestamp: February 26, 2021, 03:36:28 am
content: The scope has been (or at least was) selling unlocked. Get it.

author: mvs
author_rank: Frequent Contributor
timestamp: February 26, 2021, 08:44:53 am
content: Quote from: rstofer on February 24, 2021, 12:10:21 pm200MHz is just a marketing placement. Analog front end of the SDS1204X-E or of the unlocked SDS1104X-E do have around 300MHz bandwidth at -3dB.1GSa/s ADCs are more or less the limiting factor for a qualitative analysis on this devices.

author: wizard69
author_rank: Super Contributor
timestamp: February 26, 2021, 12:57:37 pm
content: I never did finish reading the Charlotte thread but I will add the following as my perspective:If buying new choose a 100MHz scope over a 50MHz. The reality is the difference in price these days isn't that great.That is the simple way to put it but you should also look at the digitizer method. This especially if the A/D is shared across 4 channels.In most cases I would suggest going the 4 channel route. It would be nice if the channels supported serial decode but that isn't the reason I'd prefer to see you buy a 4 channel scope. The primary reason is that you can often benefit from having more than two channels. One example here is a quadrature encoder with a zero pulse. Then there is the potential dive into motor control robotics and other activities. If you can afford them those two extra channels can be very handy.As for features that is really up to you and your intended uses. One often overlooked feature, that most scopes today have, is the ability to save waveform and data. This can be a direct connection to your network, USB or sneaker netting the data. A scope that doesn't have this capability isn't worth the bother as far as I'm concerned. If your interests (as stated) are digital, then support for serial line decode can be worthwhile. Just realize that there are dozens of low cost logic analyzer solutions on the market and there are other ways to sniff some of the serial interfaces.As for the cost of whatever scope you choose realize that if you don't blow it up a scope can be useful for 20 years or more. That would be 7300 days. So a $500 scope would cost you ≈ 7 cents a day. Obviously what I'm after here is to get you to look at the long game and not the initial price. It is far better to get a scope that fit your use case than to buy too little.

author: sairfan1
author_rank: Frequent Contributor
timestamp: February 26, 2021, 02:46:55 pm
content: I have two questions here:What is difference between Rigol 1104Z and 1104Z Plus, i googled it looks like Plus can't be unlocked,Does it worth to buy used 1104z scope around $300-$350 or better to spend more and buy new.

author: mvs
author_rank: Frequent Contributor
timestamp: February 26, 2021, 03:07:12 pm
content: Quote from: sairfan1 on February 26, 2021, 02:46:55 pmPlus version has port for digital inputs, but unfortunately no probes.

author: sairfan1
author_rank: Frequent Contributor
timestamp: February 26, 2021, 03:31:43 pm
content: I also read somewhere that plus version has hardware that can be activated through key, like decoding communication protocols, higher clock etc, just wanted to know if that's true.

author: mvs
author_rank: Frequent Contributor
timestamp: February 26, 2021, 03:53:57 pm
content: Quote from: sairfan1 on February 26, 2021, 03:31:43 pmIt is not a plus version only feature and Rigol shipps since a couple of years 1xxxZ series with many optional features already enabled for free (advanced triggers, serial decoder, 12M memory, recording). With Riglol hack you should be able to enable the rest, like more bandwidth, 24M memory, 0.5mV vertical.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: February 26, 2021, 08:51:13 pm
content: These comments and the referenced threads go into a lot of detail about minutia about the best scopes on the market today in a particular market segment. I actually don't disagree with any of the technical information, but want to provide a different perspective.Ten years from now it is highly likely that much more capability will be available at that price point. And ten years from now, you will have either gotten much more advanced in the hobby/profession or left it completely. In either case your needs will be significantly different, and what is available to meet those needs will have changed.If your budget is tight, which is presumably why you are looking at this market segment you might be better off buying a used scope, perhaps less capable, but more than adequate to get you started. For about a quarter of the price of the scopes being discussed you can get a DSO or even an older analog scope that will allow you to do most or all of what you want when working with microprocessors. The savings can be used on projects, saved for a future buy of the "perfect" scope or whatever. After a couple of years working with this older scope you will have a much better understanding of what you want the next time around. And once you have your new toy you can decide whether you need two scopes (a path many on this forum have taken) or recoup part of the cost be selling it to another beginner.

author: Electro Fan
author_rank: Super Contributor
timestamp: February 27, 2021, 12:28:30 am
content: Quote from: sairfan1 on February 24, 2021, 02:24:25 amGiven the use cases you have in mind I think you should go with a digital oscilloscope. It's true that analog scopes can sometimes be had for nearly free but even if they don't require some on-going parts and labor to keep running they will likely not be as satisfying as a new digital scope for the uC, etc work you have in mind.As for Siglent and Rigol either will be fine. You should study the differences and it will help you learn a lot about scopes before you even get your hands on one or the other. Rigol was out front for awhile several years ago but Siglent has done an excellent job of introducing new scopes and adding new features.As for which model, some of the key considerations are of course 2 vs 4 channels and how much bandwidth.I think for your interests you will find that 4 channels is preferable. Some scopes are "MSOs" and will enable you to add (typically) 16 digital channels. While the extra digital channels would be a nice to have (ideally in the form of an upgrade path where you could add a ribbon cable for the digital channels later), with a 4 channel scope and built in support for serial protocols such as I2C, SPI, UART/RS232, and possibly others you will be off to a very good start. Having said that, the support for digital signal decoding and analysis varies from model to model and it's possible that you will also want a USB logic analyzer that can cost anywhere from $10 on eBay to $100-$200 or more - but you should probably start at the entry level with an eBay special and free Sigrok PulseView software to get some nearly free experience with LAs. Frankly, you could start now with an entry eBay or Amazon LA and it might help you think about some of the features you want in a scope for your uC work.As to how much bandwidth you need, given your use cases you can probably live with 50 MHz but if you can find a way to 100 MHz or 200 MHz without stressing your budget, more bandwidth is pretty much always better. I think 100 MHz should handle your interests well and any more would be icing on the cake if you can get it.I've had a Rigol MSO for several years and I like it a lot but I'm pretty sure if was spending ~$300 - ~$1400 today I'd buy the best Siglent model my budget would allow.Here is another thread with some similar discussions:https://www.eevblog.com/forum/beginners/is-this-oscilloscope-perhaps-the-best-for-the-beginner/Keep studying and keep framing your questions, and enjoy the journey.PS, there will probably be more items you want for your bench/lab so keep in mind your long range strategy. Things like DMMs, function generators, power supplies, parts, tools, and more have a way of continually calling your name and asking you to bring them home.

author: sairfan1
author_rank: Frequent Contributor
timestamp: March 02, 2021, 04:38:21 pm
content: @rstofer I decided to go for Siglent 1104X-E i checked and it looks like base model of this scope is costs around $500I have to buy separate somefirmware and hardwareif i include logic analyzer and function generator it jumps to around $900 that is close to new Rigol touch screen scope which have lots of new functions. In addition to that i will have to buy separate software for Logic Analyzer that comes free with Rigol.just wanted to know did you mean cost of a basic Siglent is $499? as we have to buy firmware/hardware that sounds like hacking is not going to add lots of extra functions like Rigol does.

author: rstofer
author_rank: Super Contributor
timestamp: March 02, 2021, 07:51:54 pm
content: Quote from: sairfan1 on March 02, 2021, 04:38:21 pmIf the topic is just buying a scope, these options wouldn't even come up. I don't think I would buy the options because I have other tools that will do as well or better.There are 8 channel logic analyzers on eBay for $11. Even cheaper at AliExpresshttps://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=logic+analyzer&_sacat=0Dave did a video on MSO options and, in the end, didn't suggest buying the option.https://youtu.be/MC9_4mpqVgUAWG: Yes but just how arbitrary is it? I have the Siglent SDG2082 and it is an amazing piece of equipment. Tied to a Siglent scope, it can be used to produce Bode' plots. But I don't have a Siglent scope, I have the Rigol.The AWG for the SDS1104X-E is a separate box with controlling firmware added to scope. I don't know what to think of that. A fair comparison might be theSDG2032SDG1032 which goes to 30 MHz (sine wave) and probably just 25 MHz for other waveforms (I didn't check the manual but that's the specs for the 2082 - 80 MHz sine wave, 25 MHz for everything else). $359 versus $266 for scope options.The SDG 2xxx series of AWGs have amazing capabilities. I can pick a fundamental frequency and then add in harmonics of varying amplitude and phase up to 8 harmonics. A truly capable AWG. I don't think I would buy the attachment just to save $93. Besides, the SDG xxxx series has a truly useful user interface, it's not just some kind of add-on.All of these things are just choices. My choice would be the SDS1104X-E with one of the SDG AWGs. I chose the 80 MHz variant for no good reason. It is unlikely I will ever work with high speed sine waves and in terms of square wave (which I will use), the limit is 25 MHz no matter which unit I buy. I don't think I understood that at the time. Square waves are the only things I am interested in as I don't do much with analog circuits.That's my opinion, SDS1104X-E andSDG2032SDG2042 (or higher if high frequency sine waves are important). Remember, the scope option only goes to 25 MHz.Edit: I messed up on the AWG part numbers. The SDG1032 is a lower cost item but the SDG2xxx series is where you probably want to be. The SDG2042 costs $499https://www.amazon.com/Siglent-Technologies-SDG2042X-Arbitrary-Function-Generators/dp/B01410O55U

author: bdunham7
author_rank: Super Contributor
timestamp: March 02, 2021, 08:05:19 pm
content: Quote from: rstofer on March 02, 2021, 07:51:54 pmSDS1104X-E + SDG2042, hack both for 200MHz and all options on the scope, 120MHz for AWG, buy the correct TP-Link dongle and if you must, the logic probe. Now you have everything you could want. Except for a huge assortment of probes, of course.

author: rstofer
author_rank: Super Contributor
timestamp: March 02, 2021, 08:10:26 pm
content: Things that Rigol has as options are standard in the Siglent SDS1104X-E. AFAIK, the only thing that needs to be unlocked is bandwidth.You'll have to do your own research on this over in the Test Equipment forum here on eevBlog.Maybe just ask which options are included and which options need to be unlocked to gain full functionality.In terms of the Rigol DS1054Z, there are several options and we could pick and choose but I would guess that most people turn on everything.

author: brucehoult
author_rank: Super Contributor
timestamp: March 03, 2021, 12:03:02 am
content: Quote from: rstofer on February 24, 2021, 11:58:38 amThe below is my unmodified DS1054 displaying the 17.2 MHz output of a HiFive1 trying to wiggle an GPIO as quickly as possible in software (loop: XOR; SW; J loop).How much of the wiggle is because the scope bandwidth is not even quite the 3rd harmonic, and how much is likely to be the output of the MCU (and level shifters) is not clean?

author: tautech
author_rank: Super Contributor
timestamp: March 03, 2021, 04:02:22 am
content: Quote from: sairfan1 on March 02, 2021, 04:38:21 pmA capable AWG to pair with a SDS1104X-E is a $ 319 SDS1032X, a 2ch unit that does both sine and square waves to 30 MHz and doesn't have the amplitude limitations of the SAG1021I or any of the inbuilt AWG's.Yes the LA probes are expensive for what they are however you can use the analog channels at the same time so can check analog signals might have some effect on the digital communications.However with a 4ch scope and 3 used for some protocol you still have 1 other to investigate what's happening in the analog domain that may be impacting on the digital stream.That said, for the rare occasions an LA rig is needed in conjunction with a 4ch scope you could save some coin and get a LA USB module and put the savings toward a standalone AWG.

author: tggzzz
author_rank: Super Contributor
timestamp: March 03, 2021, 09:39:34 am
content: Quote from: brucehoult on March 03, 2021, 12:03:02 amYou've probably missed the elephant in the room: how much is due to probing technique and breadboard construction?Show us a photo of the setup, so we can estimate the stray inductance.https://entertaininghacks.wordpress.com/2015/04/23/scope-probe-accessory-improves-signal-fidelity/

author: brucehoult
author_rank: Super Contributor
timestamp: March 03, 2021, 10:07:57 am
content: Quote from: tggzzz on March 03, 2021, 09:39:34 amThere's no breadboard. That's an Arduino-style board, with 100mm patch leads plugged into GND and GPIO 12 (on opposite sides of the board) and the probe tip and earthing alligator attached to the other end of the patch leads.Perhaps it could be improved by using header pins in the Arduino header sockets instead of patch leads. But that would be it.

author: tggzzz
author_rank: Super Contributor
timestamp: March 03, 2021, 10:41:22 am
content: Quote from: brucehoult on March 03, 2021, 10:07:57 amSo, there's 200mm patch leads plus 150mm ground lead in the circuit. The rule of thumb is that is 350nH.If we assume the probe tip capacitance is 20pF, that LC circuit will resonate at ~60MHz. That's in the same ballpark as the ~40MHz(?) ripple we see.I suggest you will see less ripple if you remove the ground lead, put a spring tip on the probe and connect that directly to the IC pins and ground.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: March 03, 2021, 01:37:03 pm
content: On a sidetrack to this thread:If you're mainly working with microcontrollers, then buy such a USD7 Logic analyser with a Cypress CY68012 something chip in it and use it with Sigrok.I use my scope for signal integrity checks but the many channels of a logic analyser and the 100+ protocol decoders that you get with Sigrok are a real advantage over an oscilloscope. You also get all the other benefits of a PC. A bigger and higher resolution monitor to show your data on, and the ability to quickly save stuff to disk for later analyses, screenshots, etc.For hardware any of the Saleaeaeae clones will do. However if you buy a generic CY7C68013A development board such as:https://sigrok.org/wiki/Lcsoft_Mini_Boardthen you even get 16 channels instead of only eight. This is really handy if you have a project with multiple UART, I2C, SPI, etc buses.

author: tggzzz
author_rank: Super Contributor
timestamp: March 03, 2021, 02:28:17 pm
content: Quote from: Doctorandus_P on March 03, 2021, 01:37:03 pmOh, yes indeed!Use analogue test equipment for analogue signals (even if they are incorrectly called digital signals), and digital test equipment for digital signals.The other advantage of a decent logic analyser is that the triggering and filtering enable you to find and concentrate on the important information.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: March 03, 2021, 02:32:03 pm
content: Digital signals do not exist!In electronics it is common to use analog signals that convey digital information, but the signals are stil analog, and that is why you need a scope to verify signal integrity first before you use a logic analyser.Especially with for example I2C, With weak pullups and high bus capacitance you violate the timing. You see it instantly on an oscilloscope, but your (cheap) LA may well trigger on somewhat different voltage levels and not reveal this at all.

author: tggzzz
author_rank: Super Contributor
timestamp: March 03, 2021, 03:13:10 pm
content: Quote from: Doctorandus_P on March 03, 2021, 02:32:03 pmOh yes they do exist, as zeros and ones! Those are produced by a digitiser, e.g.after an ADC or before a DAC in, for example, a digital radioinside a logic circuit after the receiver has "created" them byinterpretingthe voltage (or current, or light level, or...) as a digital signal. (Effectively a 1-bit ADCThat does not conflict with the points you make belowQuoteThe information can be conveyed by either digital signals or analogue signals.Overall we are in violent agreement