When to buy an oscilloscope ? - Page 1
Forum section: electronics / beginners

author: GilbouFR
author_rank: Contributor
timestamp: January 12, 2019, 11:48:24 am
content: Started learning. I bought a soldering station (Velleman 48W VTSSC50N) to have a better soldering solution than my first buy I use to learn soldering and start creating a little stock of components from hardware I found thrown at trash bins (https://www.amazon.fr/gp/product/B072V3TY94/).I have this week bought my first lab power supply and got an KPS-3010D Eventek for about 85 euro or so.I am wondering about the oscilloscope. I have absolutely no idea about how to use one but I did see Dave's video explaining voltage over time.But.. when do you buy one ? Do you buy one at the very first even while learning basics or.. should I wait until I have enough experience and will be able to use it ?It's not a budget problem, I can buy it right now. But I'm wondering if I should buy something and put it on my lab desk when I'm not going (maybe ?) to use it for some time.I have been checking for models to buy and it seems the Rigol DS1054Z is the way to go, it's about 430 euro.But I am wondering about a cheaper one that has only 2 channels, the Siglent SDS1052DL at 290 euro or even the HANTEK DSO5102P at 300.Two channels if enough or do I need 4 channels ?Thanks for advice.

author: beanflying
author_rank: Super Contributor
timestamp: January 12, 2019, 11:52:25 am
content: Rather than rehash this yet again use the advanced searchhttps://www.eevblog.com/forum/search/?advanced;search=rigol%20siglentand push the search button when you get there.Or better yet add Micsig to your shortlist

author: kg4arn
author_rank: Unknown
timestamp: January 12, 2019, 12:05:01 pm
content: For 2 vs 4 channel: I think there is already a lot of forum discussion to refer to.4 channel offers a lot of advantages that you may not need or use starting out.As to when to buy, I would say as soon as you start learning AC circuits. You will need some sort of signal generator too.

author: ttelectronic
author_rank: Regular Contributor
timestamp: January 12, 2019, 12:07:56 pm
content: I would wait until you have reason to need one. I mean, need is relative, but when you need one or would find one useful, you may have a better idea of your requirements.

author: GilbouFR
author_rank: Contributor
timestamp: January 12, 2019, 12:12:33 pm
content: Thanks. I'm going to wait a little until I need it

author: rhb
author_rank: Super Contributor
timestamp: January 12, 2019, 01:23:47 pm
content: When you need some information about a circuit that only an oscilloscope can provide.That actually happens very quickly if you start building your own test gear. Having little to no discretionary money in grad school, I built a lot of devices to substitute for instruments I did not have. But I generally did not label things, so 30 years later I have a bunch of mysteries in a box which I scavenge for parts.BTW don't be too quick to just strip junk for parts. I fished old audio gear out of the trash and repaired it in grad school using just a VOM and soldering iron and then sold it. The education was worth more than I made, but it did give me beer money for the weekend.A project to consider:Find a suitable (i.e. old) AC powered transistor radio and tap the circuit at key points so you have an RF source, an IF source and an AF source and detectors for each. I got the idea from a book I read long ago. Use RCA plugs and small shielded wire for the connections. Run the ground out to the tip of the probes, but don't connect them. Make jumpers to connect the RF, IF, AF and speaker jacks. It's a great substitute for a scope doing radio repair.Most of all.Have Fun!Regnever did it, but I'm doing a simplified version for use in audio testing at a thrift shop I help out at.

author: tggzzz
author_rank: Super Contributor
timestamp: January 12, 2019, 02:39:49 pm
content: Quote from: GilbouFR on January 12, 2019, 11:48:24 amBuy one when you need one in order to progress,andyou can't progress using your imagination and the tools around you.Knowing how to use a scope is pretty fundamental, but there is a learning curve - on top of the learning curve associated with the "basics".There is always the danger that you see something on a scope (or any other instrument) and cannot tell whether what you are seeing is the circuit, the scope/instrument, your experimental technique, or all three. The solution is to know what you expect to observe, and if you don't see it then mutate something and see if what you observe changes as you would predict.

author: spec
author_rank: Frequent Contributor
timestamp: January 12, 2019, 02:54:57 pm
content: Always delay buying a high-tech device, like a car, TV, DMM ... as long as possible. And make sure you have thoroughly investigated your actual need and specification for the item, and get to know all the leading products in a particular range. You will then find that one product will suddenly click and seem just right for you. At that stage you need to talk to the actual users of the item to get the real story. With scopes that would be some of the members on EEV (the reason I joined EEV a few years ago).To illustrate the point, when I was last looking for a new car, I narrowed the choice down to about five models. I read the reviews checked the performance, the insurance costs, and the servicing costs and finally arrived at the model that seemed just right for me.A few days later I saw the same model parked at a taxi rank, so I asked the driver what he thought of the car. His response surprised me. He said that it was a piece of *%$#@ junk and had a major problem with a part of the engine that costs a fortune to fix. He also said that the car was noisy on the motorway and uncomfortable. He said that he would be getting rid of it soon. I was rather deflated by this so asked around some more, but sure enough, the taxi driver's opinion was reflected. Naturally, I didn't buy that type of car.Why did I say to delay as long as possible? The fundamental reason is that with high-tech products the performance keeps improving and the price keeps dropping. Not only that, but today's red-hot product will be available on the second hand market for a much reduced price within a year or so. Of course, you can take this philosophy to the extreme and never buy anything (I still havent got a new car).

author: rstofer
author_rank: Super Contributor
timestamp: January 12, 2019, 02:59:57 pm
content: And watch W2AEW's tutorial which is a sticky at the top of this forum.Once you start dealing with AC circuits (filters, amplifiers) or digital circuits (Arduino, logic chips, other uCs) you will want to see the signals. I'm not going to chase the 'scope versus logic analyzer' argument down a rathole, both are useful. I use a scope a LOT more than I use a logic analyzer and I have both. Eventually, both are required but the scope comes first.

author: KL27x
author_rank: Super Contributor
timestamp: January 12, 2019, 08:30:01 pm
content: The EE related field is enormously diverse. It is possible you would rarely use a scope, if at all, even if you had one.if you are asking, you WANT to buy a scope. If you want to buy a scope, buy a scope. But the imagination and applications don't come with the scope.If a scope is going to make your life easier and/or increase your capabilities, you will be the first person to know it.If you want a scope but don't know why, you might be a candidate for a used analog scope. They are way more fun to play with and look cool on the bench.

author: rstofer
author_rank: Super Contributor
timestamp: January 12, 2019, 11:05:41 pm
content: Quote from: spec on January 12, 2019, 02:54:57 pmAnd this results in "analysis paralysis". Of course something else is coming down the line. The questions are: "When is it coming?" and "Will I be able to afford it?". A side issue is: "What do I do in the meantime?".On the low end, Rigol and Siglent have it pretty well covered. There is no reason for them to create a product that competes with the ones I have because, for the entry level, they're not going to put out the highest tech at that level and wipe out their higher level scope sales. I think we are about teched out for a while.In the end, drive a stake in the ground! This much money and no more! These minimum features and no less! Then buy something while realizing that it is the first scope, probably not the last scope. There will be evolution just as in the PC industry and how many generations of PCs have we gone through since 1980?

author: StillTrying
author_rank: Super Contributor
timestamp: January 13, 2019, 12:48:34 am
content: Quote from: GilbouFR on January 12, 2019, 11:48:24 amDon't buy a low-res LCD, and don't buy a DL+or CML+either!If you're not too bothered about budget the Siglent X-E's look good value to me.QuoteNo, wait until you need it.

author: rstofer
author_rank: Super Contributor
timestamp: January 13, 2019, 01:25:26 am
content: So, if you bought it early, you could come up with a 555 astable oscillator of variable frequency which you could use as a signal source. Then you could learn how to use the scope before you actually needed to.Now, cash flow is always a consideration but if that is relatively unimportant at the moment, look through the scope discussions that come up about every week. There are 3 or 4 entry level scopes:Rigol DS1054Z => a more mature design with 4 channels upgraded to 100 MHz (bugs are fixed)Siglent SDS1102X-E => a newer 2 channel 100 MHz scopeSiglent SDS1104X-E => a newer 4 channel 100 MHz scope that can be upgraded to 200 MHzSiglent SDS1204X-E => a newer 4 channel 200 MHz scope - identical to upgraded SDS1104X-E but more expensiveThose are the currently discussed entry level scopes. There are other players and I'm not going to chase USB scopes down a rathole. Those above are capable 'real' scopes.You can also research 2 channels versus 4 channels pretty easy because it is argued all the time. If you go into microcontrollers, you will appreciate 4 channels. If you play with audio, it won't matter.Just use a 9V battery:http://www.circuitstoday.com/variable-frequency-oscillator

author: Brumby
author_rank: Unknown
timestamp: January 13, 2019, 02:42:19 am
content: Quote from: FakeDave on January 13, 2019, 02:08:34 amExcellent approach.It is my opinion thatit is better to know what it is you wantin any purchase before parting with the cash and playing around with that type of product is, perhaps, one of the best ways to do so.Play with your analogue scope and find out what it can do. Along the way you will find out what it can't do. This is where you start making a list of the features you want - and what specifications/level of sophistication you will need in these features. This is where you begin "window shopping" and getting a feel for what is actually available in the market. This list will get refined the closer you get to actuallyneedingsome of these features - and that's when you start planning which direction your pennies will actually be sent.As stated above, premature purchasing will probably deliver you a product that will be exciting when you unbox it, but by the time youneedits features, it will likely represent an expensive investment in an underpowered feature set.In short - it's always best to know what it is you want before you go out and get something.Edit: typo

author: spec
author_rank: Frequent Contributor
timestamp: January 13, 2019, 07:50:33 am
content: Quote from: rstofer on January 12, 2019, 11:05:41 pmAnd this results in buying a product that you may regret. It is much better to take you time and get a scope that you will be happy with for years. Buy wise and buy once is the saying.

author: rstofer
author_rank: Super Contributor
timestamp: January 13, 2019, 04:21:19 pm
content: Quote from: spec on January 13, 2019, 07:50:33 amAt this moment in time (the 'time' stake), there are 4 scopes commonly discussed. Five years from now there will likely be others. So, go for what is currently recommended or wait 5 years to see what comes up next? And, in the meantime, what? Go without?Used DSOs will probably hold their value and are pretty cheap considering their educational value. Get one, get started and if something better comes along, sell the existing scope and buy the 'new shiny thing'. Never bet against technology, something better WILL come along - someday.As to the 'loss' in value - just consider the education gained and remember that education is never free. Suppose the loss on a DS1054Z was $100 and the OP got 4 years of use. $25 per year or wait 4 years for something 'better'?

author: jazper
author_rank: Regular Contributor
timestamp: January 14, 2019, 11:41:43 pm
content: As early as you can afford it. How much scope, well that depends on your budget but if that means an analog scope, get an analog scope.The key thing a scope will do is save you time with debugging circuits. Time is precious.

author: Electro Fan
author_rank: Super Contributor
timestamp: January 15, 2019, 04:41:35 am
content: Quote from: jazper on January 14, 2019, 11:41:43 pm+1

author: mrpackethead
author_rank: Super Contributor
timestamp: January 15, 2019, 07:33:41 am
content: Now.

author: drogus
author_rank: Contributor
timestamp: January 15, 2019, 09:32:43 am
content: I am a beginner and I bought an old analog oscilloscope for 60EUR or so (it was in Poland, but I think there's plenty of choice all over the place). I second what others wrote about buying one as soon as you can and if money is an issue (like it was in my case), an analog oscilloscope will be as good as any other for learning. While you might not need one at the moment, or you might think that you don't need one, it's an excellent tool, especially if you want to work with any kind of variable voltage, whether it's PWM or AC. I also like it that an analog oscilloscope forces you to learn about frequency to time ratio much quicker (for example: you think you have 100kHz signal, how much µS you need to set per division)

author: jazper
author_rank: Regular Contributor
timestamp: January 15, 2019, 08:25:17 pm
content: To elaborate on my earlier post:If a scope saves you 30 minutes debugging, that is 30 minutes you can spend learning more, or 30 minutes you can spend with a loved one or doing something else.My scope was purchased about a month ago, so far it has saved me over 8 hours.

author: rstofer
author_rank: Super Contributor
timestamp: January 15, 2019, 08:56:50 pm
content: Quote from: drogus on January 15, 2019, 09:32:43 amThat frequency versus time/division also applies to DSOs and picking a value will come about naturally. And you can always change the knob to get what you want.

author: tggzzz
author_rank: Super Contributor
timestamp: January 15, 2019, 09:12:56 pm
content: Quote from: jazper on January 15, 2019, 08:25:17 pmThere are three problems with that sentiment.It is equally true for other instruments such as spectrum analyser, vector network analysers, etc etc etc.You omit the learning curve, high can be very significant.A complex but poorly understood instrument leads you down all sorts of blind alleys.That doesn't imply someone shouldn't get a scope, but (in the absence of other information) it isn't a no brainer.

author: beanflying
author_rank: Super Contributor
timestamp: January 15, 2019, 11:07:55 pm
content: From the time I left Uni until I got my own scope was well over 20 years. At times not having one was a PITA and needed some educated guesses to fix a fault or drop around to a mates place to borrow his a few times a year.Now I have had one on the bench I wouldn't not have one again but if it broke today Electronics wouldn't cease because of it (or maybe I should buy a second just in case). They are a great tool used properly but not essential to all people playing with electronics depending on where they play.Recommendations to 'Buy Now' A over B but forget C from incomplete questions without knowing 'what' or if they really 'need' a product isn't an answer it is a sales pitch.

author: Mr. Scram
author_rank: Super Contributor
timestamp: January 15, 2019, 11:18:51 pm
content: Quote from: spec on January 13, 2019, 07:50:33 amHow do you know what's important to you without getting a practical feel for it? You could compare specifications until the cows come home and still end up with something not quite up your street. If I hadn't bought and simply tried a multimeter, I wouldn't have known that speed is important to me. Much more important than advanced features which look excellent on paper.Over analysing is a trap. Buying something for the first time is a starting point. Thinking you can buy something and get it right the first time isn't realistic. Do your research to ensure it's not a disaster and go from there.

author: tggzzz
author_rank: Super Contributor
timestamp: January 15, 2019, 11:37:49 pm
content: Quote from: beanflying on January 15, 2019, 11:07:55 pmI agree with all of that; very sane.But I question your TEA/GAS credentials if you only have one scope

author: beanflying
author_rank: Super Contributor
timestamp: January 15, 2019, 11:40:24 pm
content: I should have added a word 'buy a second'working'one' I do have two waiting for some loving

author: tggzzz
author_rank: Super Contributor
timestamp: January 15, 2019, 11:48:42 pm
content: Quote from: beanflying on January 15, 2019, 11:40:24 pmYou are forgivenCurrently I only have a 465 in that queue.

author: rstofer
author_rank: Super Contributor
timestamp: January 16, 2019, 01:29:26 am
content: I still think the decision is pretty easy. If a project has signals that wiggle, it's nice to be able to see them on a scope. Up until then, a DMM will do the job just fine.It would be simple if we could just say DC circuits -> DMM, AC circuits -> Scope but there is that pesky experiment of a capacitor charging. It is taught in DC Circuits. It's not until AC Circuits that we worry about the frequency response, phase shift and roll-off. Assuming some kind of square wave input (astable 555?), watching the charge and discharge curves gives a lot of intuition to how timing circuits work.

author: beanflying
author_rank: Super Contributor
timestamp: January 16, 2019, 01:48:43 am
content: No one has said not to buy an Oscilloscope. What I question is that you MUST have one and buy one NOW or ASAP no matter what it is.Time and again the question of Brand A over B comes up from people not knowing what they need or want, they just 'know' from reading here or watching YouTube they need Item 'X' (Scope, DMM, Power Supply, Iron, widget....) because 'everyone' has one.Sometimes WE need to ask WHAT the OP wants to do with Item X and is likely to do with it Long before giving a specific recommendation.

author: mrpackethead
author_rank: Super Contributor
timestamp: January 16, 2019, 04:51:51 am
content: Quote from: beanflying on January 16, 2019, 01:48:43 amDo you have a scope bean?

author: beanflying
author_rank: Super Contributor
timestamp: January 16, 2019, 05:12:41 am
content: I did have two working ones but sold off my Hantek due to non use after getting a Micsig 100Mhz 4ch with all the bells and whistles. Casually looking for a 400Mhz or better one but it is a really low priority and need with what I generally do. There is a BWD and a Philips on the shelf for restoration, these are just for fun sub 20Mhz units that cost me very little.After not having a scope at all for a long while the $100 spent on the Hantek was a good way to relearn what I needed to before moving up the food chain a bit with a much better idea of what I needed and in my case it wasn't perhaps the usual suspects.

author: tggzzz
author_rank: Super Contributor
timestamp: January 16, 2019, 10:06:47 am
content: Quote from: rstofer on January 16, 2019, 01:29:26 amIf it is an RF project, a scope is probably not the best tool.Quote"No one has said not to buy an Oscilloscope. What I question is that you MUST have one and buy one NOW or ASAP no matter what it is."

author: rstofer
author_rank: Super Contributor
timestamp: January 16, 2019, 04:21:57 pm
content: Quote from: tggzzz on January 16, 2019, 10:06:47 amFrom the OP "Started learning ...". I'm just guessing but that probably doesn't mean GHz RF design or directed energy projects. I would rather imagine it will turn out to be Arduino projects or perhaps some simple 555 projects and perhaps some transistor gadgets. LEDs seem to come up a lot. Oh, and op amps, everybody loves op amps!I would expect frequencies to be modest and voltages to be reasonable. Nothing in the OP suggests high voltage SMPSs.Well, that sounds a lot like the stuff I do and the scopes we often discuss are more than adequate. I sure wouldn't spend the money to even ship a used analog scope, much less buy one, given what the new entry level DSOs cost. With a warranty...Somehow, I have to believe these scopes would be adequate for a good long time. They're inexpensive enough to be considered disposable or even dedicated to a project. Right now my DS1054Z is hanging on top of my Comdyna GP-6 Analog Computer and there it may stay. I really need an XY display for some experiments and YT is used all the time (pun intended). The hole on top of my bench might just get filled with a Siglent SDS 1204X-E. I'm still thinking about it...The cost of ownership for something like the Rigol is pretty low. If, in a few years, it comes up inadequate to expanded interests, dedicate it to a project or sell it and buy something else. At $400, these things are really inexpensive for the capability.I haven't reread the thread but I assume the topic of the Analog Discovery 2 has come up. For a newcomer, I really think it is a mistake to overlook this tool since it is an electronics workbench in a small package. If I could only have the AD2 or the 1054, it would be the AD2. It won't handle high frequencies but there are ways to work around that problem. I did it for years with my Heathkit 10 MHz scope.I'll stand by my wiggling signals theory as the gateway for buying a scope. Even simple 555 projects are more clearly understood by watching the THR input. Sure, you can read all about the charging and discharging of the timing capacitor but you don't really know it until you see it.How do you really understand PWM or servo signals without seeing them? Yes, your project, no doubt copied and pasted from the Internet, will probably work but you still haven't actually seen why it works. You haven't 'learned' anything.Beyond simple DC voltage dividers, I don't see much future in electronics without a scope. It is the tool that lets you see what is happening and seeing is believing (and learning). Yup! If the signal wiggles, a scope is the tool to use.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: January 17, 2019, 09:35:56 pm
content: Daddy, what's a capacitor charge/discharge curve?

author: rstofer
author_rank: Super Contributor
timestamp: January 17, 2019, 09:43:33 pm
content: Very nice! Just what I was thinking about when I brought it up.Somehow Vc=Vin(1-e-t/RC) and Vc = Vin(e-t/RC) just don't do as much for me.

author: tggzzz
author_rank: Super Contributor
timestamp: January 17, 2019, 10:24:53 pm
content: Quote from: rstofer on January 17, 2019, 09:43:33 pmIt is fun to see a practical manifestation of theory. But without the theory is is just another pretty picture.So much of modern electronics requires maths that not understanding the theoretical maths is career limiting.

author: rstofer
author_rank: Super Contributor
timestamp: January 18, 2019, 02:11:33 am
content: Quote from: tggzzz on January 17, 2019, 10:24:53 pmTrue enough! Without the math there is no career. No degree either, for that matter. Engineering is nothing more than applied math. Lots and lots of math. But that's not the case for the casual hobbyist. They can get along fine with the fundamentals like Thevenin and Kirchhoff (both KVL and KCL). If they find themselves without a particular tool, there's a lot of information on the Internet.

author: vk6zgo
author_rank: Super Contributor
timestamp: January 18, 2019, 02:44:50 am
content: Quote from: rstofer on January 17, 2019, 09:43:33 pmGraph paper, pencil, & a reasonably active imagination, & you've got it!

author: rstofer
author_rank: Super Contributor
timestamp: January 18, 2019, 05:57:20 am
content: Quote from: vk6zgo on January 18, 2019, 02:44:50 amYup!Make the Y axis of the graph 10 units and scale that as 100%. The X axis should go from 0 to 6 Tau where Tau is the time constant which is R in Ohms times C in Farads. Then all you need are 7 pairs of numbers: The time constant and the percent of full voltage:Code:Tau % charge Plot0 0 (0, 0.0)1 63 (1, 6.3)2 86 (2, 8.6)3 95 (3, 9.5)4 98 (4, 9.8)5 99 (5, 9.9)6 100 (6,10.0)Connect the dots.Most people will only go to about 3 Tau and then just handwave the rest.The important part is that the capacitor is 63% charged in one time constant and fully charged in six.Or close enough...

author: rstofer
author_rank: Super Contributor
timestamp: January 18, 2019, 04:23:15 pm
content: Quote from: blueskull on January 18, 2019, 06:02:09 amWell, when you ask a group for an opinion, you have to expect some variance. In this case, the recommendations are from "never" all the way down to "tomorrow" for buying that scope.People can explain the logic behind their recommendations but, in the end, it's the OP's money and their choice to make. As I have had some kind of scope for more than 6 decades, I am biased. I can't imagine not being able to see what I'm doing. Other opinions obviously vary.