Looking for Oscilloscope Recommendations

November 15, 2009 11:26 AM

I'm a hobbyist looking to buy an oscilloscope, and I need some advice.

So, I consider myself to be an electronic hobbyist, and I've decided to take the plunge and get an oscilloscope, having used one in a lab class at school. The problem is, my budget is limited to $200-300.

I see a lot of analog scopes on eBay, like this HP model. Should I be looking for something like this? I know it's important to find a seller that guarantees the item to be working, but will an analog scope work for general hobby electronics?

The one thing I don't like about the analog scopes is the screen. So I found this Rigol one. It's a bit out of my price range, but considering that it's physically a lot smaller than a typical analog scope and has a digital screen, I could justify the added cost. But I've never heard of Rigol and I don't know if they're trustworthy.

So I guess what I'm looking for is an opinion on Rigol if anyone has used one of their scopes, and if that's not my best option, please feel free to recommend a particular brand, model, or a place I can find one for a good price. I realize that I'm not going to get a top of the line oscilloscope for $300, but if eBay is any indication, it seems like I can get something that will work for messing around with parts at home.

Thanks, AskMe!

posted by DMan to technology (17 comments total)

When you say "Hobby electronics", just what are you talking about? The most important question is the maximum signal speed the scope can reliably display, which is a function of the bandwidth of the amps and the sweep speed.

If "hobby electronics" means "audio" then you don't have a problem. State of the art in 1960 was more than fast enough for you. But if "hobby electronics" means "computers" then you need a scope that can display a few gigahertz, and that's not so easy. You probably won't get that for $300.

That 100 MHz HP scope is about 50 times too slow for computer use.
posted by Chocolate Pickle at 11:40 AM on November 15, 2009

When you say "general hobby electronics" and "messing around with parts", are you thinking analog or digital? If it has to be cheap, an analog scope is actually the better choice if you want to find noise or distortion in your amplifier, but a digital scope will be better for triggering off a complicated event on your robot's I2C bus.

On preview, what CP said.
posted by drdanger at 11:45 AM on November 15, 2009

I'm sorry, I didn't really think about that making a difference. I'm mainly interested in working with robotic parts like servos and various types of sensors, along with Arduinos and similar microcontrollers. So as far as I know, 100MHz is more than enough.
posted by DMan at 11:47 AM on November 15, 2009

There's an entirely different approach to this which has appeared in the last few years. The idea is that you put the acquisition hardware into a stand-alone module and you attach it to a laptop computer using USB 2.0. All the control software, user interface, and display is done by software in the computer. The result is overall much cheaper, since the unit doesn't have to have a display built in.

I am not recommending this product; I don't know anything about it. I'm simply pointing to it as an example of the kind of thing I'm talking about. They're selling it for $575 without probes, so it's very much outside your price range.
posted by Chocolate Pickle at 11:48 AM on November 15, 2009

Argh! You guys keep bringing things up that I meant to address in the original question, my apologies.

I've heard of USB scopes and I considered that, but I would really prefer to not involve the computer. Having used both types of scope, I find the stand-alone units to be easier to use. Also, my computer is across the room from my "lab bench", and it'd be kind of annoying to have to carry parts over there to measure signals.

Thanks for the help so far.
posted by DMan at 11:54 AM on November 15, 2009

If you want cheap, USB oscilloscopes are the way to go!

I have this. It's a few years old, so its sampling rate is pretty low (I think it samples at 500khz so 250khz is the fastest signal it do anything with). For signals slower than that, it's fantastic. (Small & portable, and fairly powerful)

This is a newer product (by a different company) that has a much higher sampling rate. I haven't used it so I can't comment about the quality.

I haven't seen any USB scopes that have Mac software (some are reported to work well under vmware though). So if you still have that Alienware laptop, that might be worth looking into.
posted by aubilenon at 12:05 PM on November 15, 2009

Reconsider the USB scope. Combine it with a tiny little netbook and you'll have a nice scope though it will set you back more than $200.
posted by chairface at 12:09 PM on November 15, 2009

Rigol is a Chinese-based company that makes low-end scopes. They have been in business for quite a while. According to this website, Agilent Technologies works with Rigol. (Agilent Technologies was spun out of H-P in 1999 and has the test and measurement line from H-P).

Tektronix and LeCroy are the other big names in scopes.

Disclaimer: I am currently employed by Tektronix and I used to work for Agilent.
posted by elmay at 12:10 PM on November 15, 2009

Hmm. Well I do have a netbook that I could use. I guess I'm just old fashioned about the idea, but if it's going to give me a higher quality product for a cheaper price, I may be going that route.

Interesting to hear that about Rigol; the 'scope I use at school (undergrad EE lab) is made by Agilent and I really like it.
posted by DMan at 1:04 PM on November 15, 2009

There's discussion of a $50 oscilloscope here.
posted by cropshy at 1:07 PM on November 15, 2009

Locate a Tek TDS320. 500 MS/S and 100 MHz BW. Two channel. If possible, find one with a serial interface.

USB scopes are mostly toys for folks who don't know better. You need a trigger machine and decent front end. Large record length is like a large penis. Not necessary to get the job done. What you are talking about is certainly 100 MHz territory. If I can do what I do with one, you sure as hell can.

Ebay example: $300.
TDS200 series...

Visit/join the Yahoo! Tekscopes group. Old timers with good advice.

Rules of thumb:

Bandwidth / 10 = 1% amplitude accuracy
Bandwidth / 3 = 3% amplitude accuracy

Scope probes are critical.

Get the Tek publication: XYZs of Oscilloscopes.
posted by FauxScot at 2:04 PM on November 15, 2009

I have an old 100MHz analog scope I got from my university--seems they used to do a fair bit of EE in their CS program. It's circa 1970, I believe.

As I went looking for mine, I went through about five or six other ones that turned on and appeared to trace a signal. But the signal they traced was total garbage, bearing only blurry, fuzzy, jagged resemblance to the sine wave I was pushing from the test generator.

So, beware ancient surplus gear that claims to "work".
posted by Netzapper at 3:05 PM on November 15, 2009

As an American, you should be able to pick up a TDS-210 pretty cheap, that is probably your answer. I'm sure FauxScot's recommendation is good, a TDS-210 takes 1/3rd the space, and has a bit better specs for not that much more money. Both would come in over budget for you though..

I've got a Hantek USB scope, it works, but I find it endlessly annoying. Missing features, difficult to adjust ranges, etc. It isn't garbage, and I've been able to make good use of it from time to time, but it isn't what you want as your primary bench tool even for occasional use.

In general, if an analog scope's screen is bright and focuses properly, you can see far far more information than you can on a digital scope. Don't jump to a quick conclusion about analog just because it is old.

If your budget is too tight to allow a TDS-210, you can get a very nice analog scope for under $200. Tektronix 465 is a classic recommendation, but you don't have to go HP or Tek. Anything in the 60-249MHz analog categories on ebay should be fine.
posted by Chuckles at 3:06 PM on November 15, 2009

I spent way too much money on a 'scope, many years ago. It's a Kenwood 40MHz 2 channel, with a vestigial third channel. I still have it on my bench, I know exactly how to use every feature it has, and it works great for microcontroller projects (I do ARM and AVR stuff, with CPU speeds up to 50 ~ 80MHz. And... you can buy one for $88).

I'd bet may old analog scopes in the $100-200 range would be adequate, and a lot better than nothing.
posted by spacewrench at 5:58 PM on November 15, 2009

Dave Jones at www.eevblog.com does video reviews of electronics equipment, including several oscilloscopes. He has covered Rigol before and seems to like them for the price. I highly recommend his blog for all things electrical. Early in the archives there's a whole show about o-scopes and which factors are important to look for. Good luck!
posted by RobotNinja at 3:00 AM on November 16, 2009

Well, thanks for all the recommendations. I really like the Rigol digital scopes for their size and to me the screen seems easier to read, but it's hard for me to justify since I can get an analog scope for about half the price. So I'm going to do that for now, either a Tek or HP model, most likely.

Thanks for that about eevblog--pretty cool site.
posted by DMan at 11:40 AM on November 16, 2009

Call THE BLACK HOLE in Los Alamos New Mexico.

http://blackholesurplus.com/
posted by Oireachtac at 12:35 PM on November 17, 2009