How seriously should I be considering an oscilloscoope?

[MJay82]

Hello bunch.

So now I have my multimeter in hand. I was talking with my physics professor about how I was hoping to start designing music effects equipment(primarily MIDI controllers and guitar effects pedals) and I asked him if an oscilloscope would help me with that endeavor. He said that I more-or-less must have an oscilloscope to do such - so I'm thinking that now is as good a time as ever to purchase one, because I want to go ahead and begin dallying with designs.

I'm assuming that an oscilloscope would also be a very useful tool to help me as I move through the Bachelor's curriculum - so I'll pay for something if it's going to pay back in spades.

I know that these are expensive items. I hope not to break the bank - but as I mentioned in my multimeter thread, I live on a restricted budget so I can purchase items that will help with my studies. So should I go ahead and get one?

I did some poking around on Amazon, and I was mostly unsurprised to see that there aren't many analog models still available. I was hoping for an analog and figured I would get out cheaper that way - but I'm not familiar enough yet to even be completely sure of my needs, or what my best bet is.

This $400 digital model (Rigol DS1052E - 50 MHz) got great reviews - is this a worthwhile investment? I would have to say that $400 is definitely scraping the ceiling of my budget for this, but if this will provide functionality long into the future (I take very good care of my things) I can bear the expense today. The best time to plant an oak tree was thirty year's ago, but the second best time's today.

 

[schip666!]

A scope is essential to figuring out where you've gone wrong in your circuit theory...

You might look at USB digital scopes that connect to your computer, like the Bitscope (I presume it still exists, but there are others if you search). If you keep to the audio range you don't need a high bandwidth device. They often include logic analyzers, which can be useful in your MIDI chases too.

 

[sophiecentaur]

I would agree with schip. If your computer display is available where you do your projects (e.g. a laptop) you can spend all the 'scope money on the scope function and have the display / memory etc available for free. Also there will almost certainly be easy facilties for analysing your data directly.
But read all the specs carefully and do a lot of comparing. Best to wait rather than to rush into the first thing you happen to fancy. Get selection advice from a constructors' forum, too.

 

[MJay82]

Thanks for the advice schip and sophie.

"Constructor's forum"? I'm guessing you mean a specific circuit-designer's forum group? Can you recommend any reputable ones? There seem to be twenty bogus forum groups for every good one.

My physics teacher was telling me that oscilloscopes that interface with your computer often have lag-time issues and cannot get down much past milliseconds - but he might not be up on the latest technology.

 

[schip666!]

Well, I've had an ELAB-080 Digital scope for a few years now and the results are mixed. It (usually) works pretty good. It's (supposed) to have an 80MHz bandwidth but I generally use it below 10Mhz so I don't really care. Yes there is a lag, as it samples in the box and then sends the whole chunk of data to the PC. There are other functional idiosyncrasies, but -- given that it has a 16 bit logic capture/analyzer, arbitrary function generator, a few misc clock and voltage outputs, a spectrum analyzer display, and that it can save the captured data or images, it fills a big test equipment hole in a small space. Too bad it doesn't seem to be for sale anymore...but there are others out there.

 

[Topher925]

PC based oscilloscopes have their place, but that place isn't on a workbench for typical electronics work. In general, PC based scopes are a very poor value compared to similarly priced stand alone units. Here's Dave to tell you why: http://www.eevblog.com/2009/06/17/e...ased-digital-storage-oscilloscope-comparison/

I would look at getting a second hand DSO from a reputable manufacturer like Tektronix, Lecroy, or Agilent. You can often find TDS 2xx series scopes from Tektronix for well under $400 on places like craigslist and ebay if you look hard enough. I got my Agilent this way and have been extremely happy with it.

If you want to buy something new, that Rigol 1052E is a good choice and can be hacked to 100MHz. I personally would spend the extra $15 and get this Instek 1062A as its got 2M of memory depth: http://www.tequipment.net/InstekGDS-1062A.html

As with most things, you buy cheap, you buy twice.

 

[Mike_In_Plano]

Yep, pretty hard to have fun without a scope. Doesn't require much of one - dual channel, 10MHz will still be plenty of fun when playing with a good many circuits. I've seen a lot of old 50-100MHz machines floating about that needed some tender loving care with some spray cleaner. My favs are old Teks.
I've played with PC interfaced scopes and they've been nothing but frustration. Knowing 99% about how to build a scope doesn't quite get there...

 

[MATLABdude]

There may or may not be some bargains to be found on (quite decent) more-than-slightly used analog scopes on eBay, Craigslist and the likes. They're frequently quite heavy and/or bulky, so make sure you factor in the cost of shipping and/or can do local pickup.

That said, a scope is nice and all, but as an amateur / hobbyist (and I say that with no disrespect, having been there myself), it's not strictly necessary, so don't break the bank getting one that's massively overspec'd. If you have some access to one of the teaching (or even research) laboratories (e.g. because you haven't pissed off lab TAs and/or technicians), you can probably ask really nicely for those occasions where you absolutely, positively need to use one.

In addition to the BitScope already mentioned, there's an outfit selling a build-your-own scope with comparable specs (and a display, along with USB output):
http://seeedstudio.com/depot/

A friend of mine bought one, but the unassembled kit is still sitting in his basement.

 

[MJay82]

Thanks for all the advice, everyone.

 

[MJay82]

That said, a scope is nice and all, but as an amateur / hobbyist (and I say that with no disrespect, having been there myself), it's not strictly necessary, so don't break the bank getting one that's massively overspec'd. If you have some access to one of the teaching (or even research) laboratories (e.g. because you haven't pissed off lab TAs and/or technicians), you can probably ask really nicely for those occasions where you absolutely, positively need to use one.

MLd - I don't know if I'd lump a student actively pursuing an EE degree in with amateurs/hobbyists, but I do take your meaning. That being said, I'm looking to the future. I doubt equivalent technology will be cheaper in 3 years when I get done with my Bachelor's, and I feel like having an oscilloscope would really bring home the learning for the remainder of my degree work. Yes, this would take all of my "free" money (that which isn't in 'dire circumstance' savings), but that's really what it's for anyway.

I'm taking my core classes at a smaller college, and the physics laboratory pretty much has classes from the time the building is opened until the time it's closed, so unfortunately using the lab won't be an option.

I saw one of those kits for $60 on Amazon, but there wasn't a bit of information on it. Does the kit just need wiring and a box or what? I'm familiar with the way an oscilloscope works, and I can't conceptualize how I'd go about designing the vertical and horizontal parallel-plate capacitors to accurately sweep the electron beam across the screen. Does the kit have this built in?

 

[MJay82]

PC based oscilloscopes have their place, but that place isn't on a workbench for typical electronics work. In general, PC based scopes are a very poor value compared to similarly priced stand alone units. Here's Dave to tell you why: http://www.eevblog.com/2009/06/17/e...ased-digital-storage-oscilloscope-comparison/

I would look at getting a second hand DSO from a reputable manufacturer like Tektronix, Lecroy, or Agilent. You can often find TDS 2xx series scopes from Tektronix for well under $400 on places like craigslist and ebay if you look hard enough. I got my Agilent this way and have been extremely happy with it.

If you want to buy something new, that Rigol 1052E is a good choice and can be hacked to 100MHz. I personally would spend the extra $15 and get this Instek 1062A as its got 2M of memory depth: http://www.tequipment.net/InstekGDS-1062A.html

As with most things, you buy cheap, you buy twice.

Thanks Topher. I like this Instek unit. I will consider it for deeper evaluation this weekend.

 

[Fish4Fun]

MJay82,

I would consider a DSO an "essential tool" to anyone who actually builds and debugs circuits, but I am NOT an engineer, I am a hobbyist. Simulation software has come a very long way, and many of the things that use to require breadboards, scopes and meters now can all be worked out quite nicely in simulation.

As far as an analog versus a digital scope...having used both, I can say for general debugging a DSO is FAR MORE USEFUL. Capture length (memory depth) is perhaps the single most important feature to look for.

My Instek GDS820 just died after 8 years of very difficult life (until recently, my shop was in the garage in a salt air environment.) I would love to replace it with a 4 channel Lecroy WaveSurfer (~$6k), but I will quite likely order the Instek GDS-1062A Topher linked to above, because at the end of the day, most of what I work with is < 25Mhz and this is just a hobby for me.

I would urge you to consider new over used in most cases simply because you rarely really know how much abuse a used piece of equipment has been exposed to. Additionally, the price to performance ratio on DSOs has improved tremendously in the past 10 years. I paid close to $1000 for my GDS820, the GDS1062A for ~$400 has much deeper memory, a color screen and numerous interface options that make it seem like a great value.

As a final note, from a strictly educational point-of-view, I would not think a personal scope would be requisite unless you wanted to pursue extra-curricular activities in circuit design. Most of EE is math and science, these are the tools that are the most important to your ultimate success as an engineering student.

Good Luck and Best Wishes in whatever you decide!

Fish

 

[mdjensen22]

As a student, you could most likely get student loans to cover your test equipment or at least write it off come tax-time (justified as an educational expense). I'm not sure if that might help open your budget or not, but it might be something to consider.

At any rate, if you decide to get a PC-based o-scope, I would also suggest getting a usb-usb isolator so you don't kill your computer.
For example - http://www.bb-elec.com/product_family.asp?FamilyId=651

If you go with a standalone, would strongly recommend something with USB or other communications protocol. Especially as a student, embedding waveforms in reports goes a long way. The one that Topher recommended looks pretty good.

 

[MATLABdude]

MLd - I don't know if I'd lump a student actively pursuing an EE degree in with amateurs/hobbyists, but I do take your meaning. That being said, I'm looking to the future. I doubt equivalent technology will be cheaper in 3 years when I get done with my Bachelor's, and I feel like having an oscilloscope would really bring home the learning for the remainder of my degree work. Yes, this would take all of my "free" money (that which isn't in 'dire circumstance' savings), but that's really what it's for anyway.

I'm taking my core classes at a smaller college, and the physics laboratory pretty much has classes from the time the building is opened until the time it's closed, so unfortunately using the lab won't be an option.

I saw one of those kits for $60 on Amazon, but there wasn't a bit of information on it. Does the kit just need wiring and a box or what? I'm familiar with the way an oscilloscope works, and I can't conceptualize how I'd go about designing the vertical and horizontal parallel-plate capacitors to accurately sweep the electron beam across the screen. Does the kit have this built in?

Having gotten most of an EE degree (I was actually in Engineering Physics, but was considered more of an electronics guy than some of the actual EEs), and having worked with EE undergrads through the last 5 years, I agree with Fish4Fun. Having a personal scope is great if you do extensive electronics work, but not particularly important if you're doing the standard EE degree--your labs will provide the necessary instrumentation (and training). It's important to note that while all electronics engineers are EEs[*] not all EEs are electronics engineers.

If you do go into electronics (hobbyist or otherwise), then they're invaluable. Through my undergrad, I was part of a robotics project and had access to a scope that way. Actually, I was the one that advocated spending the $1300 (at the time) on the scope because we kept on borrowing lab ones. A personal one? That's between you and your wallet

The Seeedstudio ones have specs written up, if I recall correctly. If you look at the site, the DIY one is an assemble-this-kit style, not just the plans / instructions.[*] In terms of what people specialize in during their EE degrees--here in Canada, you can't legally call yourself an engineer without an engineering degree. In the US, you can be an engineer (of whatever flavour) if you consider yourself one.

 

[MJay82]

Okay - this is what I thought. I ought to have an oscilloscope for what I want to do. To say I gave the decision a bit of prudent thought, I will wait until Monday to make sure that this is the direction I want/feel I should take.

I'm thinking I'll get this Instek 1062A.