Is An Oscilloscope Practical - Page 1
Forum section: electronics / beginners

author: tvl
author_rank: Newbie
timestamp: January 02, 2019, 07:26:30 pm
content: Remove

author: tooki
author_rank: Super Contributor
timestamp: January 02, 2019, 07:30:21 pm
content: I’m not sure what your end goal is, but I (as someone who does electronics purely as a hobby), I found that getting a scope massively improved my understanding of real world circuits. Without a scope, we’re essentially blind to signals.So if you are going to doelectronics, my vote would be an unqualified “yes!”But if you’re going to do moreelectricalwork, the value drops tremendously. (Never mind that scoping mains safely is non-trivial when not using a specially isolated scope like the Fluke ScopeMeters.)

author: tggzzz
author_rank: Super Contributor
timestamp: January 02, 2019, 08:00:34 pm
content: For anything "mains related" makeverysure you have the right probes, lest you damage your equipment and/or yourself.Never disconnect a scope's protective mains earth.FFI about probing, especially w.r.t. safety, seehttps://entertaininghacks.wordpress.com/library-2/scope-probe-reference-material/

author: soldar
author_rank: Super Contributor
timestamp: January 02, 2019, 08:01:45 pm
content: Quote from: tvl on January 02, 2019, 07:26:30 pmA scope will give you a view of what is happening in a circuit which no other instrument can give you. If you just want to see the output of your genset then it is probably not worth buying one unless you have plenty to spend. If you are going to be building and troubleshooting electronic circuits then yes. If you are not entirely sure you can always buy a cheap/used unit and move up later if warranted or resell it if it turns out you are not using it.I have a *really* old Hameg and it works fine for my limited needs. I do not need it often but when I need it I really do need it.I remember when I was beginning and I had an audio amplifier which I had built and I just could not get it to work. After too many wasted hours trying to troubleshoot the darn thing I got a scope and hooked it up and immediately the cause became apparent: the dang thing was oscillating at some hundred KHz. Of course, there was no way to see this on my multimeter.

author: GregDunn
author_rank: Frequent Contributor
timestamp: January 02, 2019, 08:05:04 pm
content: Yes, if you're looking at signals, a scope is vital. Even when looking at DC, many meters provide a filtered value which obscures noise and ripple behavior. I just built a linear power supply and seeing the actual trace of the voltage input to the regulator made it an easy job to optimize the capacitance so that the result stayed above the dropout value regardless of the load. It also shows any spikes on the waveform which might indicate issues.And, of course, measuring mains voltage is always a concern unless you can isolate it adequately from neutral; but even then, some kind of scope is extremely helpful to see what your AC looks like. Distortion or asymmetry might indicate power distribution issues or even home wiring problems. You won't be able to analyze those with a meter.

author: james_s
author_rank: Super Contributor
timestamp: January 02, 2019, 08:09:42 pm
content: This seems like one of those cases where an older, basic analog scope would be ideal. Something like a 20-50MHz instrument which you should be able to pick up for <$50 with a little luck depending on your location. Unless you've got money to burn or are planning to seriously pursue electronics as a hobby there is little benefit to spending hundreds on a fancy new scope.

author: james_s
author_rank: Super Contributor
timestamp: January 02, 2019, 08:24:45 pm
content: Well don't rush out and pay top dollar for an old scope, but you might find one for little or nothing. I've given away two scopes over the past few years, there are a lot of older analog scopes collecting dust in closets and garages, it's worth a look around.There are lots of ways of learning electronics, books, youtube videos, websites, it helps to have an idea of what you want to do.

author: rstofer
author_rank: Super Contributor
timestamp: January 02, 2019, 08:35:22 pm
content: Quote from: tvl on January 02, 2019, 08:11:22 pmIn the electrical realm, they're pretty useless. Even if you know a utility waveform is trash, what are you going to be able to do about it? I don't probe mains, there's nothing there I can improve.For electronics, if your goal is to learn electronics as a hobby, yes, a scope is almost required. Watch W2AEW's transistor video to see examples of how he uses a scope.If you want to do educational circuits, I have a couple of points to make: First, you not only need to see the output, you need to be able to generate the input. In the video above, the author doesn't make a point of showing his signal generator. Second, there is a cheaper and better way to get started. Consider the Analog Discovery 2. It has a 2 channel signal generator, a 2 channel scope, a 2 output power supply, 16 bits of digital IO and a host of 'tools' in software. For students and those just coming in to the hobby, this is an ideal tool.Watch the lab videos to get an idea of how the AD 2 is used in practice. The first 2 or 3 lab videos should get you started. Take the whole class if you want but the math does get going by chapter 3.https://learn.digilentinc.com/classroom/realanalog/To follow along with the course, you probably need the "Pro Bundle"https://learn.digilentinc.com/classroom/realanalog/and the analog parts kithttps://store.digilentinc.com/analog-parts-kit-by-analog-devices-companion-parts-kit-for-the-analog-discovery/You can download the Waveforms software and play in Demo mode just to get a feel for the tools provided.Just look at the Features:https://store.digilentinc.com/analog-discovery-2-100msps-usb-oscilloscope-logic-analyzer-and-variable-power-supply/

author: Kleinstein
author_rank: Super Contributor
timestamp: January 02, 2019, 08:44:00 pm
content: There are different ways of learning electronics. One is more hands on the real instruments and a soldering iron.At least for the beginning a lot can be done without a scope, e.g. with just a DMM. So there may not be a hurry to get the scope and one could wait for a good offer.One can also learn quite a bit from the theoretical side - e.g. reading and using simulators.There are also cheap scope like tools, like using the soundboard or a µC board. This maybe sufficient for the very basic experiments, though these are quite limited (e.g. low BW so one may not see an OP oscillating).

author: rstofer
author_rank: Super Contributor
timestamp: January 02, 2019, 08:51:11 pm
content: Understanding circuits requires Ohm's Law E=I*R or Voltage = Current times Resistance. This is the first important concept and it is profound. Here's an example of how it would show up in a hobby environment:Say you have a red LED and you find out somewhere, like the datasheet, that it will drop 1.65V (Vfspec) with a current of 20 mA (Ifspec). You have a 5V supply and you know you want to drive the LED in accordance with the numbers above. How to size the dropping resistor?Well, the resistor has to drop what the LED doesn't (series circuit, same current through every component) so (5 - 1.65) or 3.35V at 20 mA. R = E / I = 3.35 / 0.020 = 167.5 Ohms. Well, the closest I have is the common 220 Ohms, good enough! I chose a bigger resistor to guarantee lower current. The LED won't be maximally bright but it will be bright enough.https://www.alliedelec.com/m/d/6355b8aba0b01578df0bb7b871ceefd7.pdfThe point is, you can't even light an LED without Ohm's Law. Or, you could just remember 220 Ohms for a red LED on 5 volts.Actually, you might try 470 Ohms and find it bright enough. Maybe even 1000 Ohms. But at least you know the lower bound - 167.5 OhmsRight after that we get to circuit analysis and things get more complex. I really like the Real Analog program at Digilent (linked above) You might try the Electrical Engineering program at Khan Academy.

author: soldar
author_rank: Super Contributor
timestamp: January 02, 2019, 09:53:50 pm
content: Quote from: tvl on January 02, 2019, 08:11:22 pmNo, a scope is not going to help you understand. I would recommend a lot of reading online, videos, etc. that explain how things work. Then, when you want to build and troubleshoot that is when you need the tool.If you do not know if you need something then you don't need it. When you get to the point where you think you need a scope for a particular purpose then you need it. You will know you could use a scope for a purpose when you have the knowledge. The scope does not bring the knowledge. You have to supply that. You need to gain the understanding first. Then you need the tools to use that knowledge that you have. Again, you can spend hours learning from online resources without spending a dime and without leaving the comfort of your chair.

author: tooki
author_rank: Super Contributor
timestamp: January 03, 2019, 02:40:37 am
content: I do not have formal training in electronics, and I found a scope to be enormously helpful in learning. When you’re reading up about electronics, it’s all theoretical when it’s on paper. Building a circuit brings it to life, and for that, you need test gear to measure and see the results.

author: Mr. Scram
author_rank: Super Contributor
timestamp: January 03, 2019, 03:30:01 am
content: Quote from: soldar on January 02, 2019, 09:53:50 pmI disagree, honestly. Both an oscilloscope and a multimeter are tremendous tools to help you understand what's going on. Without knowing what's going on in your circuit, it's very hard to get a good grasp on what is happening when and why. As you can't see electrons, both tools serve as your eyes as a substitute.

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: January 03, 2019, 10:13:51 am
content: A trainee once asked my why I was using a 'scope to check a DC supply rail. I explained that it wassupposedto be DC, but that didn'tguaranteethat it was DC.A multimeter may give the same reading whether it's DC, pulses or poorly rectified AC. For example the inexperienced guy checks a computer PSU with a multimeter, sees +5 and +12, decides it can't be the PSU and starts swapping a whole load of parts that aren't faulty.The experienced guy checks it with a scope and gets the fault rightaway, that there's a substantial AC ripple on one of the lines.Not only that but the nature of the ripple suggests a dried-up electrolytic on that rail. He peeks in through a ventilation slot and sees the bulging object behind it. Fault diagnosed.

author: Jwillis
author_rank: Super Contributor
timestamp: January 03, 2019, 10:45:28 am
content: I'm not as experience as most people here with even less experience with an oscilloscope.Wish to some day get a proper DSO. But I already find my analog an indispensable tool to find whats going on in a circuit. I would be completely blind without it and learn absolutely nothing.

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: January 03, 2019, 11:55:33 am
content: "proper DSO"DSOs do have advantages, for example storage on an analog scope will cost a fortune and involve a massive unit. However, it's the difference between seeing for yourself and having a computer tell you what it thinks it sees. The latter might sometimes be more accurate, but can also be wildly off and you won't necessarily know. For example with aliasing. Obviously price and quality play a part here!

author: soldar
author_rank: Super Contributor
timestamp: January 03, 2019, 12:17:53 pm
content: Quote from: james_s on January 02, 2019, 08:24:45 pmI agree. When you don't really know if you are going to take seriously into a certain hobby then the best course is to buy something used / low cost which can let you begin and give you a feel. If you want to get involved more deeply you can then get better equipment. There are USB oscilloscopes on ebay for very little or you can get a used older model.The main thing is that a scope is just a tool that will allow you to gain information but it is of no use if you do not know what information you need. If you have an audio amp or a power supply which you are troubleshooting you first need to understand the circuit and how it works and what signals you should expect at each point. The scope is not going to tell you that information. Once you know all that you use a scope to confirm the signals are what they should be or not. The scope does not tell you what they should be. You have to know that on your own. Like a wrench does not tell you how to fix your car, it just allows you to do it if you know how.

author: Jwillis
author_rank: Super Contributor
timestamp: January 03, 2019, 12:20:05 pm
content: All I have in a DSO is a Hantek 6022BE .It's not bad for some things but the software really sucks and crashes a lot.

author: GeoffreyF
author_rank: Regular Contributor
timestamp: January 03, 2019, 01:16:54 pm
content: I think the Rigol 1054 is a good entry level scope. The two channel version is also fine but you may wish to measure more than 2 points in your circuits.As a rule of thumb, a scope of a particular bandwidth is most useful for 1/5 of that bandwidth. A 50 mhz scope is of limited use above 10 mhz, which is fine if you are looking at Audio or microprocessor type stuff. The reason for this is that the main value of looking at a trace is the harmonics or capacitive/inductive effects on fast rise times. For that you need the extra mhz.Above about 200mhz, the skill set to get an accurate reading increases.As already mentioned, be very careful with the ground lead. If the unit under test is mains connected or grounded, I measure current between the scope ground and the ground of what I am testing before I proceed.

author: soldar
author_rank: Super Contributor
timestamp: January 03, 2019, 01:32:11 pm
content: Quote from: GeoffreyF on January 03, 2019, 01:16:54 pmYup. Before digging into a device study it carefully, especially the power supply part. If anything is not totally isolated from the mains I use an isolation transformer.

author: BillyD
author_rank: Regular Contributor
timestamp: January 03, 2019, 02:29:10 pm
content: Given that you have already have some knowledge of repairing PCs I think it's likely that you'll go at least some way beyond looking at AC waveforms for at least some of the time.Personally I'd consider those old analogue scopes very niche at this stage; while they're good for dealing with a nice clean regular repeating signal they quickly get frustrating with anything more complex.Whereas even a basic DSO will let you capture and review both once-off digital and analog signals and waveforms with ease.And, importantly, they take up a fraction of the space on the bench.A DSO opens up a whole new world of 'seeing' electricity as others have mentioned above, it's probably one of the most exciting electronic tools you can get.

author: jazper
author_rank: Regular Contributor
timestamp: January 04, 2019, 02:14:23 am
content: In that budget range you may be able to squeeze a rygol 4 channel scope which you can "tweak" to 100mhz - the venerable 1054z4 channels are better than two, and even in its default guise of 50mhz you will get a lot of value out of itIf the hobby falls through, you can always sell the scope

author: alsetalokin4017
author_rank: Super Contributor
timestamp: January 04, 2019, 02:22:55 am
content: Of course you need an oscilloscope. If you didn't, you wouldn't be asking about one on this forum! More importantly, you _want_ an oscilloscope. You know you do! And you also know that cheap tools are no bargain. So get the most scope you can afford, bearing in mind that, at present, it's like a baby: you don't know what use it might be in the future.Something like the Rigol DS1054z or the Siglent or GWInstek similar models will make you proud. If you are really on a budget and enjoy self-improvement hobbies you might consider a good used analog scope, but something tells me you can afford one of the entry-level DSOs.

author: tautech
author_rank: Super Contributor
timestamp: January 04, 2019, 02:32:06 am
content: Years ago a great friend and Dr of EE said to me if he had to choose just piece of TE it would be a good oscilloscope....it can be a Voltmeter, Frequency counter, Spectrum analyser and of course a scope.The compedant technician uses it for all these uses and I’ve sold many a SDS1202X-E into the repair industry.

author: joeqsmith
author_rank: Super Contributor
timestamp: January 04, 2019, 03:02:58 am
content: I've given three analog and a digital one away over the past few years. Maybe post your state. Who knows, maybe someone has one that lives near by. I had a guy want to give me an old Tec scope not too long ago. Maybe check Craigslist.Good luck with your new hobby and retirement.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: January 04, 2019, 03:15:49 am
content: Well, the answer is "it depends". That is, the most "bang for buck" in your price range would appear to be the Rigol DS1054z 4 channel, hacked to enable all options plus the 100 MHz bandwidth. But perhaps that is really "too much" bang. For instance I probably only use half or even fewer of the total feature set of my 1054, and I use the heck out of it for all kinds of things both hobby and semi-professional. In the latter role it has paid for itself several times over.But maybe you only actually "need" something like the Analog Discovery mentioned earlier or another USB style scope that uses your laptop as the user interface. You could get something like the basic Hantek USB thingy for under 100 dollars, even including probes. Then when you realize you actually need some more capability for a particular project .... well, perhaps it's better to have the capability in a tool and not need it, than to need it and not have it.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: January 04, 2019, 03:24:11 am
content: 4 channels or two? (Don't even consider a single channel scope unless someone gives it to you free, alongside a 2ch unit.)Well, one may very rarely need 3 or 4 channels, or 3 with external trigger. But if you don't have them... it doesn't really matter whether you need them or not, you are "SOL" as they say.Separate vertical controls for each channel, or just one set, selectable for which channel? OK.... if you rarely use 3 or 4 channels, why have their controls always there, cluttering up the panel space? Well, the extra channel encoders can always be viewed as spares, so when CH1 controls wear out you can swap the encoders for #4 over.... yeah OK that'll work.

author: jazper
author_rank: Regular Contributor
timestamp: January 04, 2019, 03:33:19 am
content: You can spend $50 for a used analogue scope and it will let you see sinewaves.You can spend $100 for a USB scopeYou can spend $250 or so on a two channel scopeYou can spend $300-350 (maybe less with a 20% eBay deal or something) on a 1054z with 4 channelsYou can spend $500 on a siglent 1104x-eYou decide what you want.I would go a 4 channel over a 2 channel any day of the week, I would go for higher frequency if it fits in my budget. 4 channels has gotten me out of trouble a few times.The siglent 1202, 1104 and the rigol 1054z are all good scopes. Ultimately it comes down to your budget

author: tautech
author_rank: Super Contributor
timestamp: January 04, 2019, 03:50:08 am
content: Quote from: tvl on January 04, 2019, 03:39:15 amIt has better specs and better features but always with 2 less channels. If you’re adamant you won’t need 4 channels it’s a good choice and yes there are cheaper options from Siglent but their specs are much lower than X-E’s and the reason why I don’t stock them.Many members here are pretty happy with what the SDS1202X-E offers.

author: rstofer
author_rank: Super Contributor
timestamp: January 04, 2019, 04:12:20 am
content: Quote from: tvl on January 04, 2019, 03:39:15 amThere is no 'hack' about it! The device was manufactured with the capability to switch between 50 MHz and 100 MHz. The other options were always turned on by entering a code. All that happens is somebody figured out how to derive the various option codes. I prefer to think of it as 'unlocking' because the capabilities are already there.Nevertheless, it's fair to take the DS1054Z off the table.QuoteThe Siglent is a couple of years newer and the UI is reported to work a lot better. In short, the SDS1202X-E is the only credible scope in your price range still on the table. Not a bad choice either!Be careful of any Rigol review more than about a year old. Rigol had teething pains (as has Siglent) and it took a few iterations of the firmware to get the problems resolved. Doesn't matter, Rigol is off the table and Siglent is the last scope standing.

author: vk6zgo
author_rank: Super Contributor
timestamp: January 04, 2019, 04:19:43 am
content: Quote from: jazper on January 04, 2019, 03:33:19 amSquare waves, rectangular waves, sawtooth waves, analog video, modulated RF, DC levels (used as a largescreen centre zero voltmeter), all with frequency content depending upon the 3dB down point of the vertical amplifier.Quotewhich, depending on what you buy, will probably battle to look at complex analog signals.Quotewhich, if it is a DSO, will be either about the same as the USB scope, or a bit betterQuoteNow you are talking about fairly decent DSOs!Quote

author: Kasper
author_rank: Frequent Contributor
timestamp: January 04, 2019, 04:41:10 am
content: Scopes are nice to have, even for a beginner.A cheaper and safer option is a simulator. LTspice is a good free simulator. It takes a bit of effort to learn but there is lots of help out there.

author: Fungus
author_rank: Super Contributor
timestamp: January 04, 2019, 11:14:56 am
content: Quote from: tvl on January 04, 2019, 03:39:15 amYou wouldn't need to hack one to look at the sine wave of mains AC. The base model has about 1000x the bandwidth needed for that.The "hack" is no big deal, just enter a number by pushing buttons on the front panel and everything unlocks. It can also be reset/removed if you want.Quote from: tvl on January 04, 2019, 03:39:15 amBoth have pros and cons but they're really very similar at the end of the day.OTOH the Siglent costs more and you only get two channels.

author: james_s
author_rank: Super Contributor
timestamp: January 04, 2019, 04:46:25 pm
content: Looking at the sine wave coming out of the wall or a generator will keep you entertained for about 5 minutes, then what? *Any* scope will work for that, even one of those ancient Heathkit, Eico, etc vacuum tube scopes that have about a 500kHz bandwidth.Maybe you can borrow a scope from someone for a bit to play around and decide if it's something you want to spend a few hundred bucks on? It doesn't make sense to buy an expensive instrument if it ends up collecting dust once the novelty wears off.

author: Fungus
author_rank: Super Contributor
timestamp: January 04, 2019, 04:53:47 pm
content: Quote from: james_s on January 04, 2019, 04:46:25 pmOr get one ofthese.

author: soldar
author_rank: Super Contributor
timestamp: January 04, 2019, 05:56:12 pm
content: Quote from: Fungus on January 04, 2019, 04:53:47 pmYou know, I realize that is not going to replace a real scope but I would find that useful very often because my scope is an old CRT type and very inconvenient to move. I already have more handheld instruments than I need but I might be looking at one of those.

author: Fungus
author_rank: Super Contributor
timestamp: January 04, 2019, 06:20:56 pm
content: Quote from: soldar on January 04, 2019, 05:56:12 pmThere's a thread on those,here.They're only good up to a few kHz but they're very portable and it's enough to show you the the shape of a generator/inverter's output.

author: dnwheeler
author_rank: Regular Contributor
timestamp: January 04, 2019, 07:43:58 pm
content: When trying to decide between 2 and 4 channels, consider if you might want to do protocol analysis. Most digital scopes have the ability to decode serial protocols using multiple channels. SPI, for example, typically uses 3 or 4 channels (clock, MOSI, MSIO, and CS). Even I2C uses two. Having additional channels allows you to decode a serial signal and still be able to watch additional signals at the same time.Don't forget that most digital scopes have a built-in signal generator, too.

author: james_s
author_rank: Super Contributor
timestamp: January 04, 2019, 07:50:08 pm
content: But if you want to decode SPI for example, a small logic analyzer is really a better tool for that job. If you're already poking around with a scope then it can be handy to be able to do that with the scope as well, but it's not really necessary when very cheap PC based logic analyzers are available.I've never had a scope with a built in signal generator but I wouldn't place much value in that feature, it's unlikely to be as good as a separate signal generator. I like tools that focus on doing one task well rather than the "everything and the kitchen sink" approach.

author: Cactus
author_rank: Contributor
timestamp: January 04, 2019, 09:24:55 pm
content: I'm a almost a complete beginner I understand some of the basics but I rely on the knowledge of others to get me by as I learn. I own two scopes, the first one is a basic old analogue Beckman industrial 20mhz scope which i picked up for £30 the other is a labnation smartscope that i can connect to a pc and it cost significantly more. Many will have opinions about my choices but they suited me at the time. They are not necessarily a recommendation for you.You are retired and you are looking to play around and learn a bit. Its a few months yet until I retire but I too was looking to learn and enjoy a new hobby. The enjoyment I got from using an old scope was worth every penny. The hour I spent chatting to the retired electronics engineer who I bought the scope from was worth far more than I paid him, and playing about with it taught me much about these mysterious devices.Whether a scope is practical for you I cannot say. But I would encourage you to buy one either new or used and have some fun with it and see where your interests take you. If you find its not for you then sell it. If you buy a used scope wisely you might even make your money back if you sell. The most important thing is that you enjoy your retirement.

author: tggzzz
author_rank: Super Contributor
timestamp: January 04, 2019, 10:07:22 pm
content: Those are sane comments, cactus.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: January 04, 2019, 10:14:20 pm
content: Some example scopeshots from the Rigol 1054z in my lab:

author: Electro Fan
author_rank: Super Contributor
timestamp: January 05, 2019, 02:46:55 am
content: Lots of good advice in this thread already but here are some more thoughts.If you are looking to learn and enjoy electronics as part of your retirement you are almost for sure headed for an oscilloscope. And maybe more than one. There is another thread about how 19 scopes are what you need to reach “par.”Before you head for multiple scopes it’s probably good to start with one. My suggestion would be to purchase a Rigol DS1054Z, and to order it from TEquipment.https://www.tequipment.net/Rigol/DS1054Z/Digital-Oscilloscopes/?v=0It lists for $375 including shipping and it also includes Rigol’s bundle of software options. With this scope you can do power supply work, other analog work, and also explore some digital work including RS-232, I2C, and SPI. This doesn’t mean you might not still want a logic analyzer some day but it will get you started with digital which can be useful and fun.TEquipment offers a discount for EEVers, so it might be closer to $350 all in, and they offer a 60 day money back guarantee. (Disclaimer: I have no affiliation with TEquipment other than being a happy customer.)If you want to save more, TEquipment currently has an open box 1054Z for $265.https://www.tequipment.net/Rigol/DS1054Z-B/Digital-Oscilloscopes/• One thing to check on with the open box deal is whether the bundled software comes with itEither way, you could spend more on a scope with other features but the 1054Z will get you going and you will have a ton of people here who will be able to walk you through almost anything related to this model. Some people here will say much the same about the Siglent scopes. I haven’t used a Siglent scope but I have used a Siglent 2042X waveform generator and it is excellent. You’ll find plenty of Siglent vs Rigol opinions here. I have had a couple Rigol scopes and also 3 Tektronix analog scopes and IMO I think you will be able to learn and do a lot with the Rigol 1054Z.One reason to consider keeping the price down on the scope is that once you get going with this hobby you might find plenty of other items to add to your bench. Along this line, suggestions would be to include 2 DMMs, a power supply, and probably some sort of waveform generator. With these plus some breadboards and component parts plus EEVblog, youtube, and rest of the Internet you can teach yourself plenty and do lots of build and/or repair projects – you will be limited mostly by your time and imagination, although possibly to some extent by the budget because it can be an endless journey of more test equipment, components and supplies, and tools. As soon as you graduate from the breadboards you’ll be soldering - another addition to the budget. And it can go on and on… microscopes, spectrum analyzers, ham radio, microcontrollers, logic analyzers, etc, etc. It really doesn’t have to be too expensive, but outside of RF work the scope might be one of the larger budget items and it all adds up. So leave some room in the budget (and on your bench / in your lab) for growth. Hard to say what you might run out of first: time, money, or space - but probably not fun.All of it can be a blast and I'm confident you will very much enjoy using your scope. Something about visualizing analog and digital signals together on a scope makes a whole lot of concepts and some of the math more tangible and accessible.Have fun and Happy New Year!!

author: rstofer
author_rank: Super Contributor
timestamp: January 05, 2019, 05:22:44 am
content: Quote from: tvl on January 05, 2019, 03:11:35 amBuying a used scope is always high risk. Even if you decide to return it, you eat the shipping (usually). In my view, this is an advanced topic. And fixing a scope generally requires a scope.OTOH, a dozen or more years ago I paid about $200 for a used Tektronics 485 scope and I have been using it ever since. Well, right up until I bought the DS1054Z. It's a great scope with 350 MHz of bandwidth.I got lucky!As to LA versus scope, I will go for the scope every time when I'm working on something simple like SPI. The scope is right there on the bench, I'm probably probing things anyway, I've just looked at CS' framing so I might as well hook up the other two probes and see if the data looks reasonable.I've got a couple of LAs but the only time I used them is on FPGA projects where I wanted to keep track of the state variable and a few signals. There's no point in doing that any more because Vivado has the ILA (Internal Logic Analyzer). It doesn't even need wires!Everybody comes up with their own processes.

author: Fungus
author_rank: Super Contributor
timestamp: January 05, 2019, 07:51:52 am
content: Quote from: tvl on January 05, 2019, 03:11:35 amYep. I think the world has reached a point where nobody's dumping analog 'scopes any more and the only people trading them think they're something special and price accordingly.Plus they're all old and falling apart and maintaining them usually needs a second oscilloscope. If you don't have more than one of them you could end up with a large brick.As a source of "cheap oscilloscope for beginner", analog isn't the way to go. Not any more.My advice is to bite the bullet and spend the $350 on a Rigol DS1054Z, or, if you have no absolutely no interest in microcontrollers, a 2-channel Siglent.These days all the fun is in microcontrollers though. If your aim is to get a new hobby then that's probably the place to be.

author: BravoV
author_rank: Super Contributor
timestamp: January 05, 2019, 10:15:50 am
content: Quote from: tvl on January 02, 2019, 07:26:30 pmQuote from: tvl on January 05, 2019, 03:11:35 amReading above your own words, ask your self this ...As you just entering this early retirement period to have some fun, are you ready to waste your energy, time and resources spent for fixing an old scope ? Even its dirt cheap.Not to mention most of the cases you need an "extra" working scope to fix that broken scope, and also there is no guarantee it can be fixed, even you're experienced and skillful to fix it, as some old scopes have unobtainium parts.If you determined that you're going to have fun fixing it and take a gamble on it, then go buy old scope.But if you don't like this idea, protect your self at least 1 year from the new scope warranty.My 1/4w resistor worth of advice,

author: Old Printer
author_rank: Frequent Contributor
timestamp: January 05, 2019, 04:45:15 pm
content: Consider what has been said about the other tools you will need. A decent DMM is a must, and two are better, but they have become very cheap and as long as you stay out of mains voltages $50 buys you a nice meter. Once you have your scope you will likely want to add a variable power supply or two and a signal generator. I went the Analog Discovery route while teaching myself and have never been sorry. Not cheap at about $300 but the software is very good and mature, something lacking in most low priced USB scopes. Also it is a power supply, signal generator, 16 channel logic analyser, spectrum analyser and a few more. All geared toward learning. After buying a new one I found an older model on eBay for $50 for my grandson. If you are interested in learning electronics it will allow you to explore many different areas.

author: Electro Fan
author_rank: Super Contributor
timestamp: January 05, 2019, 07:16:28 pm
content: After re-reading your original post I should have noticed that you already have many meters. And DuPont is of course a very seriously capable company. So given that you repaired equipment there you probably are up to speed on Ohm's Law and can read schematics, which would probably indicate you are pretty familiar with the workings of discrete components including resistors, capacitors, and inductors, and maybe transistors? And various ICs? Maybe it would help if you could tell us more about the components and circuits you have worked on or would like to work on, and roughly how much math and theory you have accumulated.It sounds like you are interested in a combination of learning more about electronics and trying to find some practical uses of a scope and you don't want to invest in a scope unless it gets a reasonable amount of use, which is understandable. As mentioned in this thread one way to look at it is that if for some reason the scope you buy doesn't trip your trigger it should have some resale value. In horse math it should be worth roughly half of what you pay for it but maybe more depending on what you buy. So if you spend $350 you could be out $175 if it becomes a boring boat-anchor, but likely you will get several hours of interesting experience before you come to that conclusion. Kind of like the cost of taking your wife or girl friend for about 3 dinners with movies. If it's your wife I'd go for the scope, if it's your girl friend it might be a thinker. Just kidding.Quote from: tvl on January 02, 2019, 07:26:30 pm

author: alsetalokin4017
author_rank: Super Contributor
timestamp: January 05, 2019, 07:35:18 pm
content: For the open box DS1054z deal you should check for:1. original factory warranty and vendor warranty periods intact2. should come with 4 probes w/ accessories, power cord, calibration certificate3. firmware version installedThe "software bundle" is available on line, and sucks anyway, there are better opensource softwares available. Myself, I never use the software from that "bundle" at all. I use a serial terminal emulator on Linux to send SCPI commands and receive data to/from scope over LAN (like for instance to unlock or remove options), and I use DSRemote for GUI-based remote control over LAN. Everything else is built into the scope's firmware. Even if it does not come with the options unlocked it is a matter of a couple of minutes to generate the necessary key and apply it to the scope. Upgrading firmware to latest version is also simple.TEquipment is a great vendor. You should be able to call them with your questions.

author: Electro Fan
author_rank: Super Contributor
timestamp: January 05, 2019, 08:02:14 pm
content: FWIW, the open box deal says it is a 30 day money back guarantee (vs. 60 days for the factory sealed model). 30 days should be enough to determine how you feel about it, but it's good to confirm what's included and how the guarantee works. You will likely find buying from TEquipment to be a very good customer service experience.Quote from: tvl on January 05, 2019, 07:16:55 pm

author: Electro Fan
author_rank: Super Contributor
timestamp: January 05, 2019, 08:28:07 pm
content: OK, Roger all that.I'd be surprised if you don't really, really enjoy using the 1054Z.Better start reading up on JDS vs FY waveform generators.https://www.eevblog.com/forum/testgear/suggestion-choosing-an-hobby-signal-generator-(jds6600-fy6800-utg1005a)/msg1785575/#msg1785575This will be somewhat like the Rigol vs Siglent discussions. There are some other very long threads on the various FY and JDS generator versions. For somewhere around or less than $100 one of these is likely to be your most economical solution, but I'm betting you will want a waveform generator shortly after the scope arrives. The Siglent and Rigol waveform generators are nicer than FY/JDS but I think you can probably save some $ and be happy with the FY or JDS. On the other hand if you have been trained in the DuPont/Fluke school of buy once cry once then you might want a Siglent waveform generator - they are an excellent value. And if you don't already have one pretty soon you will have to search the threads for a variable power supply. Unlike entry level scopes where the battle has largely been settled in the EEV forums, power supply choices are pretty large; many makes and models to choose from.Enjoy the journey.Quote from: tvl on January 05, 2019, 08:03:44 pmYes, you are correct in stating I have many types of electrical meters ............… and, while I'm not trying to boast, I've always purchased quality meters such as Fluke, Simpson, Biddle, etc. One reason for this was because DuPont always taught it was best to use and trust only in quality instruments and the other reason is sadly my inclination to feel I always need the best ……………. or at least better than the everyday "norm". This does come at an increased cost for me, but my meters/equipment choices have always served me well.And you are also correct in stating that I am familiar with Ohm's law, print reading and such. Years ago, I completed a 2 year study in Industrial Electricity and for a while was an electrician with my employer (DuPont). My last 20 years with my employer was actually spent in the Technical organization as a resource for the plant's testing lab. In this position, I not only ensured the instrumentation was on aim, I was also a resource for the electrical shop which maintained the 24 hour support for equipment failures or off-aim conditions. I also worked closely with plant electrical engineers on equipment upgrades and was basically a "wrench" when it was time to tear out the old components and install the new. Therefore, this task, along with my everyday activities gave me ample experience troubleshooting, reading prints, etc. I'm far from an electronics engineer or advanced electronics student, but I do possess strong electrical skills. So yes, I'm familiar with discrete components, but nowhere near being able to design electronic circuitry.Anyway, I hope that helps clarify some things for you and possibly others. You did hit the nail on the head when you stated: "...……. you don't want to invest in a scope unless it gets a reasonable amount of use, which is understandable.Thanks so much!

author: Old Printer
author_rank: Frequent Contributor
timestamp: January 06, 2019, 04:06:35 am
content: A quick look on eBay shows several used 1054z scopes ranging from mid $200,'s to $325. This is an Improvement from 6-8 months ago where it would be hard to find one used for sale. Buying a new 1054 then selling it a year later is likely to net you 75% of the purchase price and a quick sale. That's a pretty safe market for testing the waters.

author: exe
author_rank: Unknown
timestamp: January 06, 2019, 10:50:10 am
content: I have dedicated power supplies, an oscilloscope, a wavegen, a bunch of dmms, a logic analyzer, but most of the time I use analog discovery 2. It's not a high-performance device, but for most purposes it's sufficient. It also save bench real estate and always at hand (read makes me more productive).Disclaimer: I mostly work with frequencies below 10MHz, often below 1MHz.

author: Fungus
author_rank: Super Contributor
timestamp: January 06, 2019, 04:37:56 pm
content: Yep, the Analog Discovery 2 is a great little learning device.

author: Electro Fan
author_rank: Super Contributor
timestamp: January 06, 2019, 07:23:53 pm
content: +1 for Analog Discovery 2It is a great learning device with a lot of functionsGood Summary of the features/functions, specs, and some user reviews:https://store.digilentinc.com/analog-discovery-2-100msps-usb-oscilloscope-logic-analyzer-and-variable-power-supply/?utm_source=google_search&utm_medium=ppc&utm_campaign=AD2_pro_oscilloscope_customers&utm_content=action_2&gclid=EAIaIQobChMIo6q4rOrZ3wIVRp7ACh2EjQR4EAAYASAAEgLfS_D_BwEBy the time you add some accessories (probes, adapters, etc) the price (unless you are a student) is similar to Rigol and Siglent entry scopes. In return for giving up some bandwidth and sampling you get a lot of tools in one compact device. The other tradeoff is you get a PC/Mac interface rather than a knob/button interface.Different horses for different courses but if these tradeoffs trip your trigger it is a wonderfully feature rich learning tool. If the budget permits a case could possibly be made for an AD2 plus a scope.

author: KL27x
author_rank: Super Contributor
timestamp: January 07, 2019, 12:33:26 pm
content: QuoteIn my own situation, the scope is a necessary evil. It gets an "unreasonable" amount of use. But when I need a scope, I need a scope. I think if you needed a scope, you would be the first one to know about it.

author: VIO47
author_rank: Newbie
timestamp: January 09, 2019, 03:36:38 pm
content: Hi EEVblog Users,I just registered on this forum and this is my first posting here. Hope this topic is the right place for my question, I don't think I should open a new topic only for a question.I am a hobbyist in electronics and about one month ago I bought an oscilloscope SDS1202x-e. It is my first one and I hope it was a good choice, until now it helped me a lot. I did not intend to spend too much money only for hobby activities and I like very much the SPI and I2C decoding abilities included for free.One question I have now, hope somebody can clarify here; the user manual is only summary and I couldn't find too much information. I have noted that the oscilloscope is able to show a correct rectangular signal shape up to about 2 MHz, at 4 MHz the shape is no more rectangular, the corners gets rounded, at much higher frequencies it shows more like sinus signal. Is this normal? Since the oscilloscope can go up to 200 MHz, I have seen a test at 250 MHz too, sinus signal of course, I was thinking it should work correctly with rectangular signal at frequencies higher than 2 MHz, at least the SPI frequencies. Anyway, on SPI the decoding works very well even with that distorted signal.

author: Fungus
author_rank: Super Contributor
timestamp: January 09, 2019, 03:44:28 pm
content: Quote from: VIO47 on January 09, 2019, 03:36:38 pmIt depends on the signal source, the way you connect the probeandthe oscilloscope settings.Three variables about which we have no information.

author: VIO47
author_rank: Newbie
timestamp: January 09, 2019, 03:56:31 pm
content: For this test I have used a ST32F103 board, signal was generated by PWM timer, test probes connected directly on the board pins, I have started with "Auto Setup" and then I tried to improve the shape using manual settings as much as I know now but without success. Maybe the STM32 is not able to provide a clean rectangular signal at higher frequencies? I am playing with STM since some time but I didn't have an oscilloscope until now.

author: exe
author_rank: Unknown
timestamp: January 09, 2019, 04:52:32 pm
content: Quote from: VIO47 on January 09, 2019, 03:36:38 pmBe sure that 1) signal source can really produce square wave of that frequency 2) you have 10x probes 3) proper probe compensation 4) proper probing techniques.

author: tautech
author_rank: Super Contributor
timestamp: January 09, 2019, 05:04:12 pm
content: Quote from: VIO47 on January 09, 2019, 03:36:38 pmWelcome to the forum.As with all DSO waveform reconstruction issues, please ensure the firmware is the latest version, V1.3.23. (SDS1202X-E)Link:https://www.siglenteu.com/download/6573/Next, signal source, probing technique and/or input type has everything to do with the fidelity of square waves.See this thread for examples, good and bad and advice on suitable connection methods.https://www.eevblog.com/forum/testgear/show-us-your-square-wave/Particularly the signal source quality, as frequency increases the risetime of the leading edge becomes more difficult to remain as 'ideal' or perfect. Even when slow, for digital comms it won't matter ifalledges have the same risetime.

author: rstofer
author_rank: Super Contributor
timestamp: January 09, 2019, 05:33:51 pm
content: Quote from: exe on January 09, 2019, 04:52:32 pmMake sure you have set the probes to 10x and have the channel configured for 10x. You should get pretty decent waveforms out to about 25 MHz (figuring 9th harmonic is still in the -3 dB bandwidth). The waveform may still be acceptable out to 50 MHz if the -3dB point is around 250 MHz.

author: VIO47
author_rank: Newbie
timestamp: January 09, 2019, 06:47:52 pm
content: Thank you all for the replies. I have checked the probes compensation and adjusted it first time when I received the oscilloscope. Regarding the source, indeed it may not be the best one, so I think I should trust more the oscilloscope and less the micro controller. Switching the probe on 10x makes a huge difference, I didn't thought it is so important. I intended to attach 2 pictures but I cannot post back my message with the pictures attached (size is below 2000kB).Regarding the firmware, it's a bit strange, I have software version 7.1.3.17R1 and this is not listed on Siglent website. Or maybe the version I have is 1.3.17R1 (without leading 7) and then V1.3.23. is a newer one?

author: rstofer
author_rank: Super Contributor
timestamp: January 09, 2019, 07:06:02 pm
content: Watch Dave's video:He talks specifically about your bandwidth issue

author: tautech
author_rank: Super Contributor
timestamp: January 09, 2019, 07:06:30 pm
content: Quote from: VIO47 on January 09, 2019, 06:47:52 pmIt's due to a far less capacitive loading of the circuit when using 10x probe setting.QuoteFor screenshots use the blue Print button to save a png file to a USB stick.QuoteYes, install V23 at your earliest convenience, it offers many improvements to the UI.View the release notes here:https://www.siglenteu.com/wp-content/uploads/dlm_uploads/2018/09/SDS1000X-E_Release_Notes.pdf

author: VIO47
author_rank: Newbie
timestamp: January 09, 2019, 07:58:31 pm
content: Thank you for the video, very good explanation. I will install the last version of firmware. I have the .png files on my laptop, captured with EasyScope but I get error "504 Gateway Time-out" here on the website when I attach the pictures, they have 750 KB each.

author: tggzzz
author_rank: Super Contributor
timestamp: January 09, 2019, 08:02:10 pm
content: Quote from: exe on January 09, 2019, 04:52:32 pmThe frequency is irrelevant; only the risetime is important.https://entertaininghacks.wordpress.com/2018/05/08/digital-signal-integrity-and-bandwidth-signals-risetime-is-important-period-is-irrelevant/

author: tautech
author_rank: Super Contributor
timestamp: January 09, 2019, 08:15:45 pm
content: Quote from: VIO47 on January 09, 2019, 07:58:31 pmQuoteIt's easier to get them onto a USB stick where they are only a few 10's of KB each.Like I mentioned before, use the blue Print button on the front of the scope to get the display capture.

author: VIO47
author_rank: Newbie
timestamp: January 09, 2019, 08:38:51 pm
content: The 2 pictures attached, hope it works this time.

author: Electro Fan
author_rank: Super Contributor
timestamp: January 09, 2019, 10:34:12 pm
content: Hi VIO47. As exe and others have said it is possible that several factors are involved but I am betting that the limitation you are seeing is not your probing technique - rather the limitation is the capability to generate the "rectangular" waveform you were anticipating in the first place. And as tggzzz points out the underlying factor is rise time. (This is not to minimize the importance of probe technique including good probe grounding to minimize ringing. This video by W2AEW is definitely worth watching:- but the larger issue you are facing is bandwidth and bandwidth’s relationship to rise time.)I realize you are using a ST32F103 board with a PWM timer but if for example we were to look at the specs on a Siglent SDG2122X waveform generator that produces a 120 MHz maximum output frequency for sine waves we would see that the 2122X produces a maximum 25 MHz square wave, with a 9 ns rise time. If we were to look at an even more expensive Agilent 33522B waveform generator we would see that it has a 30 MHz maximum bandwidth sine wave and it produces a maximum 30 MHz square wave, with a 8.4 ns rise time. In general, when you look at the sales literature for waveform generators they consistently emphasize the maximum frequency or bandwidth as being that of the sine wave produced. Other waveforms such as square waves and pulses will sometimes/generally/often be produced at lower frequencies. Of course, each make and model of generator employs some techniques that will influence the ability of the generator to create the desired waveforms with integrity – but bandwidth is a fundamental consideration and rise time is related to bandwidth.The following articles gives formulas showing the relationship between bandwidth (as expressed by frequency) and rise time.https://www.edn.com/electronics-blogs/bogatin-s-rules-of-thumb/4424573/Rule-of-Thumb--1--The-bandwidth-of-a-signal-from-its-rise-timeAs mentioned, for various reasons the 0.35 "rule of thumb" is a rule of a thumb rather than an absolute. Nonetheless, using the rule of thumb I have attached a copy of a spreadsheet showing simple calculations for several frequencies - this provides a quick glance at the relationship between bandwidth and rise time. The spreadsheet gives the rise time (Tr) results in nanoseconds (ns) and picoseconds (ps).At the top we see that a 20 MHz bandwidth will yield a rise time of about 17.5 ns. We see that 70 MHz (the clock speed I think on your STM32F103) can potentially yield a rise time of 5.0 ns. Further down we see a 200 MHz bandwidth will yield a rise time of 1.75 ns, and a 400 MHz bandwidth will yield a rise time of 0.875 ns or 875 ps.To help describe what you might visualize along these lines, if you were to connect an Agilent 33522B generator (rated to produce a 30 MHz square wave with a 8.4 ns risetime) to a 400 MHz Tektronix 2467B oscilloscope and you set the Agilent to produce a square wave with a frequency of 5 MHz you would get something on the Tek scope that would look reasonably like a square wave. But if you turned the frequency dial on the Agilent generator upward by the time you reached 30 MHz on the generator you would think the 400 MHz scope was displaying something that looks much more like a sine wave than a square wave.(Keep in mind that when we measure rise time we are generally looking at the time it takes a rising slope to go from 10% of it's peak amplitude to 90% of it's peak amplitude.)To help further describe what things might look like at higher speeds we find that 10 GHz could yield a 35 ps rise time. So while a 200 MHz scope would seem pretty “snappy” (not a technical term) in it’s ability to produce a 1.75 ns rise time if we could see a rising slope at 1.75 ns next to a rising slope at 35 ps we would think the 35 ps waveform is headed almost “straight up” and the 1.75 ns waveform by comparison looks pretty “diagonal”. Regardless of our ability to put human adjectives on what we see with our eyes, our test equipment can give us measurable results and what we associate with square vs rounded or diagonal is best presented quantifiably as rise time – which is a function of bandwidth. And in the end our test equipment is kind of like the proverbial chain in which the weakest link (either the bandwidth of the waveform generator or the bandwidth oscilloscope) determines our ability to generate and measure rise time.One other observation about your observation. When I first got into studying this stuff I thought a square wave would be an ideal waveform to help keep track of clock timing and to ensure the integrity of data encoding and decoding but as you mentioned your signals are decoding properly even with a "distorted signal” (which I think means a non-rectangular looking signal you are seeing on your scope). Welcome to the magic of both digital technology in general and of test equipment in particular that lets us both quantifiably measure and visually observe electricity as it is manipulated for various purposes including the ability to represent digital (binary) data riding upon analog (continuously variable) signals.Quote from: exe on January 09, 2019, 04:52:32 pm

author: VIO47
author_rank: Newbie
timestamp: January 09, 2019, 11:15:37 pm
content: Thank you Electro Fan, definitely I have a lot to learn about using the oscilloscope.

author: Electro Fan
author_rank: Super Contributor
timestamp: January 10, 2019, 01:04:05 am
content: You are doing A-OKOn your 10X setup have your scope show you the rise time.Quote from: VIO47 on January 09, 2019, 11:15:37 pm