How do I know when to buy an oscilloscope? - Page 1
Forum section: electronics / testgear

author: dany-boy
author_rank: Contributor
timestamp: March 04, 2015, 01:56:38 pm
content: Hello everyone:I'm a 17 year old Mexican student and electronics hobbyist, and I'm convinced that I will be an electronics engineer. Over the years I have bought my own equipment and I now have pretty much all the basics, many tools, a good soldering iron, multimeters, power supplies, basic function generator and lots of assorted components. Recently I came across a project for which an oscilloscope would have been handy. So I have come to the point to ask; Do I need and oscilloscope?I was hoping you guys could tell me when is it a good time to buy such an important piece of equipment.Thanks a lot

author: jadew
author_rank: Frequent Contributor
timestamp: March 04, 2015, 02:00:02 pm
content: Hi and welcome to the forum.The sooner the better - it's going to be one of the most useful tools on your bench and odds of regretting the decision to buy one are extremely slim.

author: AndyC_772
author_rank: Super Contributor
timestamp: March 04, 2015, 02:08:58 pm
content: I survived without one for a long time, but that was more out of necessity than anything else. 'Scopes were expensive.That's no longer the case. Now we have Ebay, where you can take a bit of a risk and buy an old (but probably perfectly good) scope for a fraction of what it would have cost new. Or, you can just buy a brand new one like a DS1054Z.If you can afford one, go for it. It's a standard lab instrument, so once you've got one, you'll use it all the time.

author: tggzzz
author_rank: Super Contributor
timestamp: March 04, 2015, 04:29:52 pm
content: If you don't know why youneedand oscilloscope, then clearly you don't need an oscilloscope!

author: Lightages
author_rank: Unknown
timestamp: March 04, 2015, 04:34:57 pm
content: I can't think of a time where a oscilloscope was not a benefit in my past. Well maybe when I was just starting it wasn't "needed". You can do lots of things without a scope but you will never regret having one, especially when things don't work the way you wanted.

author: hans
author_rank: Super Contributor
timestamp: March 04, 2015, 04:37:34 pm
content: Consider a scope as your eyes in electronics.Without one you're basically blind or sight impaired. It makes things very though to debug, especially anything above 3Hz which a multimeter can't keep up with.I consider it as a must have. You can sometimes figure stuff out with interpretation and more testing, but it's just so tedious to do and not very efficient way of working.

author: PeterFW
author_rank: Frequent Contributor
timestamp: March 04, 2015, 05:07:21 pm
content: Quote from: tggzzz on March 04, 2015, 04:29:52 pmI thought that too, for year and years i was told i should get one but i never saw the need.Last year i bought one, after something i wanted to build dit not work and i could not determine why.Looking back i wish i could tell my younger self to "Suck it up and buy a damn scope!".I only wish i would have bought a different one from the one i now have but i regret the decision not in the least.One of the most usefull tools i have ever addet to my workbench.If only to help you understand and see what is happening in the circuit, it is one thing to "know" why it should work but it is so much better so "see" why it works or not.But it should be a DSO and no analog, i think if i had bought a analog scope as i first wanted the story would have been different.Everyone should have a DSO, even it if it is a crappy china scope, in most cases they will do just fine.

author: dany-boy
author_rank: Contributor
timestamp: March 04, 2015, 06:36:29 pm
content: Thank you very much for all of your quick replies! after doing some research I think the Rigol DS1052e or DS1054z are both good options for an entry scope. I'll get one as soon as I can, here in Mexico things are scarce and expensive though...

author: PeterFW
author_rank: Frequent Contributor
timestamp: March 04, 2015, 06:43:23 pm
content: Quote from: dany-boy on March 04, 2015, 06:36:29 pmI bought the DS1052E because everyone said, it is the go to scope.A few months later they relased the DS1054 and i was pretty damn bummed out, and i still am. It was a big chunk of money and awfull timing, if i just had waited a month longer...It might be that a Hantek Scope will do just fine for you, they are 100$ cheaper then the DS1054.I might be using it wrong but the tiny screen of the DS1052E is rather annoying, would not recommend buying one.Greetings,Peter

author: teddy529
author_rank: Contributor
timestamp: March 04, 2015, 08:56:10 pm
content: The sooner the better.Scope is one of the most frequently used equipment on lab bench, actually, the most used equipment.It goes scope - DMM - Power supply

author: Neganur
author_rank: Unknown
timestamp: March 04, 2015, 09:05:38 pm
content: At this time I would not get the 1052e either, there is simply no reason not to go for the newer Rgol instead.But back then, before all the newer scopes, the 1052e was fine.Peter, I think it's a good idea to try and sell the old scope for maybe 180 eur and get the other Rigol - If you use the instrument a lot.And don't be sad about products getting old so quickly nowadays, look at the Agilent X-series 2000/3000, they've been out since uh Feb 2011? I bought mine April last year and now the 3000T is out. Of course its not that much different in comparison to the Rigol-change but had I known back then, I would also have waited a year and buy the new model instead. And who knows, the next model is due soon too! So if it's a real deal breaker I would sell the old item and get the newer one instead of being dissatisfied. Otherwise, stuff is pretty much outdated the moment you buy it anyway!

author: Adal
author_rank: Contributor
timestamp: March 06, 2015, 08:25:01 pm
content: When I´m a student I don´t have a scope. I use the school scopesIn México, exist a few options to purchase a new oscilloscope, some are:www.radiosurtidora.comhttp://tienda.distele.com/MEXICO_D.F.htmlhttp://www.finaltest.com.mx/Personally, my scopes are acquired locally when they appears in flea markets or in our "Craig list"They work, with some issues, but work.If you need USB/GPIB ports for documentation, control and whatever, and have a lot of money buy a new scope. If not, use your ingenious! You are a engineer. Buy a good second hand scope digital or analog. Not pay much please for a used equipment!

author: McBryce
author_rank: Super Contributor
timestamp: March 06, 2015, 09:18:55 pm
content: Quote from: PeterFW on March 04, 2015, 05:07:21 pmI wouldn't fully agree with you here. As a general purpose scope, a DSO is definitely the best choice. But there are certain situations where a DSO just can't give you what a good old Analogue scope can. It all depends on what type of electronics you intend focusing on. I use my DSO most, but I still wouldn't part with my analogue (Tektronix 2465).McBryce.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 07, 2015, 12:29:39 pm
content: Quote from: McBryce on March 06, 2015, 09:18:55 pmFor example? I mean aside from building an engineering museum?At the end of there's probably a reason analog scopes are no longer in production for more than a decade, and I'm pretty sure if there were situations where an analog scope would be better that they still would be made.An old analog scope is fine for a beginner if the scope is free or really cheap, but that's about it. Spending any noticeable money on an analog boat anchor would be silly.QuoteMaybe, but my feeling is that this is because you probably haven't used a decent DSO yet.

author: tggzzz
author_rank: Super Contributor
timestamp: March 07, 2015, 03:45:44 pm
content: Quote from: Wuerstchenhund on March 07, 2015, 12:29:39 pmWell, people that are far betteranalogueengineers than you and I prefer analogue scopes for very well-articulated reasons. Google for "Robert Widlar" or "Bob Pease" for well-known examples.You might also like to understand what Fenichel came to appreciate:https://www.eevblog.com/forum/projects/chua-chaos-circuit/msg613014/#msg613014QuoteAh, the certainty of youth and inexperience. There are many pharmaceuticals that are no longer available, not because they are no good but because the manufacturer can makemore moneyfrom newer drugs that are still protected by patents.QuoteOn a boat anchor, I'd agree. But there are other reasons why analogue can have advantages in some situations.

author: Ericho
author_rank: Regular Contributor
timestamp: March 07, 2015, 04:46:00 pm
content: Do I need and oscilloscope?I was hoping you guys could tell me when is it a good time to buy such an important piece of equipment.I would argue, Yes you need one urgently, A todays model, digital.If possible something like a DS1054Z, learn about every last function you can find in there while playing with it.

author: Neganur
author_rank: Unknown
timestamp: March 07, 2015, 04:49:08 pm
content: I'm probably going to burn my mouth on this one, but:Widlar, Pease and Williams lived in a different time. Different technologies available, different habits, different needs. Those guys did not use DSOs much because they were crap when they were in their best days. Especially Pease is in my eyes also a very stubborn old hat when it comes to computers (which DSOs basically are too). I don't think you can do analog design any more without simulations (I'm not talking about 7805 power supplies).Then there is also the experience factor. Those folks lived while it was all being developed and have a much more intimate relation to the devices (because they designed the components, thinking Widlar for example). Very often they could do things without instruments at first because they knew how circuits would behave because they've seen it before and have understood why. In my very humble opinion it has nothing to do with the CRO being better than the DSO. This is pure professional expertise (which those three fellas had tons of).If I look at myself as reference, I was presented with analogue electronics from a perspective of all of the 'modern' stuff that is around today. Why on earth would I use an analogue oscilloscope? The specs of the DSOs at work are much much better than the CROs 20 years ago. And the need for circuit simulation is also there because that's how big companies plan and develop their products.At last a quick story about an 'old fart' in the tunnel digging business here in Finland. The ground is solid rock and you need to use explosives to dig. The spots where the explosives are placed is carefully calculated by a computer system that did not exist when the 'old fart' was young. The device broke on his shift but he continued to correctly place the charges as he had done in many years of work. It was only later at the end of the shift that people realised that the computer was broken because the younger engineers from the next shift needed the instrument to do the task.I think that situation can be compared to the claim that CROs are better than DSOs. An experienced worker can complete tasks with them just as well. Technology moved on though and I claim that people just can't help it since they are biased towards the tools that they are familiar with.Also, I notice how it is always just claimed that "there are other reasons" why CROs can have an advantage. Not often are those reasons spelled out nor is it really obvious that you do those specialities very often.

author: Neganur
author_rank: Unknown
timestamp: March 07, 2015, 04:54:57 pm
content: Quote from: Ericho on March 07, 2015, 04:46:00 pmyou need one. you're missing out on the experience if you don't ever have one.It does not matter what kind it is as long as it's a reasonably modern one.Get a digital one if you have the choice, they are much more convenient with all the remote control, screenshot, measurements and exporting functions.You can't afford top of the range gear anyway and there is no need for it until you have a specific justifiable reason (e.g. at work, or you are self employed and your work depends on it).

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: March 07, 2015, 05:21:51 pm
content: Quote from: tggzzz on March 07, 2015, 03:45:44 pmReally, they "prefer" analog scopes? Rob Widlar died 25 years ago, so saying that hepreferredanalog scopes is a rather stupid statement when even at the time of his death digital scope technology was still in its early stages and analog scopes were still the predominant type of oscilloscope. Widlar was certainly a great analog engineer but what tools he preferred during his working life decades ago has absolutely zero relevance to tools available in 2015.Bob Pease only died in 2011 but as Widlar most of his active career was when digital scope technology was still in its infancy. He was an analog guy throughout and certainly knew his stuff, but that was analog design and not digital test instrumentation that is available in 2015.Neither of these gentlemen have any relevance to the question if getting an analog scope in this day and age makes sense.QuoteWhat, that a low-end Rigol scope performs worse at X/Y mode than an analog scope?I suggest you first try to understand that there's much more to digital scopes than what you see on a bottom-of-the-barrel Rigol.QuoteWhat utter tosh. I'm not young (but thanks for the compliment anyways!), and after roughly almost three decades don't consider myself inexperienced (and I spend a lot of time with analog scopes in the old days!).QuoteMaybe, but in 2015 analog scopes are the EE equivalent to bloodletting by leeches.QuoteOn a boat anchor, I'd agree. But there are other reasons why analogue can have advantages in some situations.And yet I'm still waiting for some specific examples were that is the case. Which you could have given instead of the irrelevant tosh.

author: smgvbest
author_rank: Unknown
timestamp: March 07, 2015, 05:50:37 pm
content: How about on my 400Mhz 4CH analog scope I can have all for channels going and not worry about aliasing issue's ahobbyistlevel DSO would have. I can't run all 4 channels and be looking at a 100Mhz signal on each one successfully without aliasing. Keep in mind this is an entry level question. on the professional side maybe the argument is moot but for the lower end ones I find value in having my analog scope when looking at more than 1 channel. I just do not loose the range I do on a entry level DSO. There's trade off on each.

author: djghost
author_rank: Contributor
timestamp: March 07, 2015, 06:09:56 pm
content: My life changed when I first got my scope : you learn a lot and you can even create a special bond with the tool

author: Neganur
author_rank: Unknown
timestamp: March 07, 2015, 06:35:02 pm
content: Quote from: smgvbest on March 07, 2015, 05:50:37 pmA 4Ch 400 MHz is hardly entry level (I'm guessing tek 2465 ?).Is aliasing on recent DSOs really an issue? Modern DSOs bandwidth limit frequencies greater than half the scope's sampling frequency (anti-alias)

author: nctnico
author_rank: Super Contributor
timestamp: March 07, 2015, 06:49:47 pm
content: Aliasing is never an issue unless the DSO has no proper peak-detect. Unfortunately some manufacturers made DSOs which didn't had preak-detect so you would have problems with aliasing. IMHO the analog versus digital discussion is nothing more than this:Versus:

author: Smith
author_rank: Frequent Contributor
timestamp: March 07, 2015, 08:42:27 pm
content: I love my scopes. I wish i bought mine years earlier. You dont always need a scope, but it can make most tasks so much easier. Especially the newer DSO's which can be used for doing all kind of measurements.If money is an issue, an analog scope will do in most cases. A DSO is great for detecting glitches and analyzing serial data.

author: Wmacky
author_rank: Regular Contributor
timestamp: March 07, 2015, 10:06:32 pm
content: So an affordable hobbyist range DSO is a better tool than an analog scope for designing / troubleshooting audio amps? This is very contrary to what I have read, unless things of changed in the last 5 years? If you talking about very expensive DSO's that would be irrelevant for me as some of us are just hobbyist and don't work in a lab at JPL.

author: nctnico
author_rank: Super Contributor
timestamp: March 07, 2015, 10:15:03 pm
content: Quote from: Wmacky on March 07, 2015, 10:06:32 pmThat is just audiophoolery talking. When I got my first (analog) scope the first thing that annoyed me was that looking at signals below 10Hz was extremely annoying. How the hell do you want to work on audio if you can't see signals below 10Hz??Besides that an oscilloscope isn't a very good tool to judge the quality and determine signal levels with absolute accuracy in general. For that you'll need a distortion/spectrum analyser and an AC voltmeter. Luckily most modern DSOs have some spectrum analysis (FFT) features.

author: markce
author_rank: Regular Contributor
timestamp: March 07, 2015, 10:21:41 pm
content: You do not need an oscilloscope. Would be handy is not enough.Buy a specific one if you're really convinced you need one, and have minimum requirements.For now, just as an experiment, buy an analog scope cheap second hand.

author: Wmacky
author_rank: Regular Contributor
timestamp: March 07, 2015, 10:29:08 pm
content: Quote from: nctnico on March 07, 2015, 10:15:03 pmInteresting. I do know that a SA would be very useful for audio, but was told the FFT function on my Rigol 1102 was useless for audio due to bit depth I believe? It was said that even a cheap Ebay audio card SA would be a better SA. Has this changed with the current generation? Say a 2072A, or even a 1054Z? That alone would push me to upgrade.

author: miguelvp
author_rank: Super Contributor
timestamp: March 07, 2015, 10:32:38 pm
content: He already has a function generator, the scope will help you make better use of it. Also buying a cheap used analog scope can be more costly, at the price of the DS1054z I wouldn't gamble on an old scope.

author: Neganur
author_rank: Unknown
timestamp: March 07, 2015, 10:46:55 pm
content: Quote from: Wmacky on March 07, 2015, 10:06:32 pmYou're not arguing for anything, you're just protesting (what exactly were the reasons stated in your source ?).Bring an example why it is worse or better in your opinion for the task you mentionedAnd since you're saying 'affordable' maybe mention an actual price range too because, as others noted, audio bandwidth does not require an X00 MHz BW analogue scope either.

author: Neganur
author_rank: Unknown
timestamp: March 07, 2015, 10:57:28 pm
content: Quote from: Wmacky on March 07, 2015, 10:29:08 pmYou can't compare a 24-bit audio card with maybe 192 kHz sampling (you said cheap ebay) with an 8-bit oscilloscope and then say that the FFT resolution sucks on the scope.You probably also would use an FFT analyser (dynamic signal analyser). But I ponder the need for such a device for troubleshooting. Characterising the performance yeah, but to find a faulty cap or bias point you're better off with a voltmeter.

author: nctnico
author_rank: Super Contributor
timestamp: March 07, 2015, 11:28:16 pm
content: FFT helps to check the bandwidth of a circuit or get a feeling about the distortion of an amplifier.

author: atferrari
author_rank: Frequent Contributor
timestamp: March 08, 2015, 12:53:55 am
content: Hey, the time is now!Buy and move on. Experience that you could collect with it is the most important.

author: Wmacky
author_rank: Regular Contributor
timestamp: March 08, 2015, 01:07:17 am
content: Quote from: Neganur on March 07, 2015, 10:46:55 pm?Perhaps it's a language barrier issue, but I don't fully understand your post. Protesting? What am I'm protesting? I had asked a question with no protest? As I stated, this advice was read, so I wouldn't have any personal examples. As to a price range, see my follow up post regarding models.

author: siggi
author_rank: Regular Contributor
timestamp: March 08, 2015, 01:08:07 am
content: Buy an oscilloscope as soon as you can. Buy the cheapest, meanest oscilloscope you can find that works. It's the difference between seeing or not - everything else is gravy.Upgrade when you need to, and when you know more....Sent from my iPad using Tapatalk

author: atferrari
author_rank: Frequent Contributor
timestamp: March 08, 2015, 01:26:10 am
content: Quote from: blueskull on March 08, 2015, 01:14:44 amOh, can't they?

author: Neganur
author_rank: Unknown
timestamp: March 08, 2015, 01:55:29 am
content: Quote from: Wmacky on March 08, 2015, 01:07:17 amYes, it's most likely language - I meant 'contradiction'* as in 'absence of agreement', 'disputing a fact', you were only opposing your own statement "DSO is a better tool for audio" without providing facts to back up the claim. I was hoping you could quote the source with its actual reasoning. Else there is no way to confirm the claim.*: perhaps this. The man wants to argue but his dialogue partner only changes the polarity of the sentences and hence, does not argue. You were protesting against your own statement about the DSO as tool for audio.But I guess you really meant to ask "are DSOsreallybetter at this?", since as you say you have no personal examples.Yeah I think that a DSO has the edge there, the analogue ones can't do FFT at all (if we're talking the Rigol 2000 or 1000 series price range), both may have 500 uV/div etc.And even for those, the ebay example you mentioned (the board I linked was just the first that came up, there are even Creative labs cards for that price) will outperform the scopes due to the dynamic range of its ADC.

author: nctnico
author_rank: Super Contributor
timestamp: March 08, 2015, 02:17:03 am
content: IMHO the digilent Analog Discovery (www.digilentinc.com/Products/Detail.cfm?NavPath=2,842,1018&Prod=ANALOG-DISCOVERY) could be an interesting tool for audio and LF use. It uses a resolution of 14bit for signal acquisition and generation. You can even use it as a vector network analyser to create a amplitude and phase response (of an audio circuit). I would trust it more than a cheap sound card.

author: EEVblog
author_rank: Unknown
timestamp: March 08, 2015, 03:37:33 am
content: Quote from: dany-boy on March 04, 2015, 01:56:38 pmYou've just answered your own question!It's right at this exact point you need to buy an oscilloscope.

author: dany-boy
author_rank: Contributor
timestamp: March 10, 2015, 02:11:25 am
content: Wow! I never though such a simple question would get so much attention and spark such an interesting discussion between DSO’s and CRO’s. Even Dave has replied to my question! Thank you very much for all of your advice and I’ll soon buy a Rigol DS1045Z as per all the positive reviews.Again, thank you very much to all of you for your amazing adviceSincerely Daniel