SparkFun Forums 

Where electronics enthusiasts find answers.

Have questions about a SparkFun product or board? This is the place to be.
User avatar
By Chewie RFC
#114009
Hello,

I'm in the market for a solid, affordable, entry level oscilloscope. I intend to use it for both digital and analog circuits. For analog, it'd be mostly medium wave RF and audio applications. For digital, microcontrollers of several megahertz. I've seen some stuff on the Rigol and Owon scopes. Is anyone familiar? I'm figuring I need at least 50MHz of BW. Any tips, suggestions, etc?
By follower
#114020
This question comes up every now and again on a few different electronics related boards. If you haven't already I'd suggest you search this forum, the arduino.cc and avrfreaks.net forums for previous threads on the topic.

--Philip;
By rrpilot
#114040
I bought the Rigol 100Mhz bandwidth scope from ebay and I really like it, I just wish it had serial communication decoding but I guess you gotta put up the $$$ for those features.
By ScottH
#114706
Look on Craigslist. Check fleamarkets and Hamventions. Check the local university surplus auctions. I got a 60 MHz scope at a garage sale once for $15. It pays to scrounge. Electronics parts shops often have a consignment area too.

I would also recommend an analog scope as a first scope. Digital scopes have lots of cool features, but analog wont fool you as much.

Don't get a PC based scope or a cheapo digital gizmo.


-Scott
By winston
#115214
I'd recommend a second hand Tektronix 100MHz bandwidth digital storage oscilloscope, I bought a mid-90s vintage one last year to replace my (also bought second hand) analogue scope. Very expensive when new, can be had reasonably cheaply now, and still a great instrument.
User avatar
By Chewie RFC
#118019
Well, I pulled the trigger and bought a Rigol DS1102E. Found one for a great price ($665) with free shipping and I just couldn't pass it up. I'm excited! I haven't used a 'scope since I was an EE student about 7 years ago!
User avatar
By Chewie RFC
#118764
Update: Just received my Rigol DS1102E on Friday. I love this thing, it's great. The FFT functionality is my favorite, by far. I tested it on an AM receiver that I built and it's fantastic. I'm glad I made this purchase.
By fll-freak
#118791
Have you had time to look at the following features?

1) Are the ground clips on the probes isolated from the scopes earth ground? My current LeCroy is not isolated making picking arbitrary ground reference points impossible as it generates a short via the earth grounds.

2) Does the unit have the ability to be connected to a PC via USB for remote operation and or data viewing/recording/printing?

3) Is the LCD display big enough and of resonable quality to look at for hours at a time?

4) How are the cursor controls for time and voltage? Can you control each one with its own knob? Can they work independantly as well as in a tracking mode?

5) Are the instructions (it does have instructions right?) in understandable English?
User avatar
By Chewie RFC
#118794
fll-freak wrote: 1) Are the ground clips on the probes isolated from the scopes earth ground? My current LeCroy is not isolated making picking arbitrary ground reference points impossible as it generates a short via the earth grounds.
Great question, I do not know. I'll get back to you.
fll-freak wrote: 2) Does the unit have the ability to be connected to a PC via USB for remote operation and or data viewing/recording/printing?
Yes, it does. I haven't installed the software, as it is Windows based and I use a Linux machine. I have heard it is really not the greatest, BUT the protocol is easily programmed and others have used Python, C, etc to make their own custom software.
fll-freak wrote: 3) Is the LCD display big enough and of resonable quality to look at for hours at a time?
Yes, it's quite nice.
fll-freak wrote: 4) How are the cursor controls for time and voltage? Can you control each one with its own knob? Can they work independantly as well as in a tracking mode?
Yes, time and voltage are independently controlled and they can be tracked, independent, or automatic.
fll-freak wrote: 5) Are the instructions (it does have instructions right?) in understandable English?
There is an instruction quick-book and a full set of instructions on the CD. The English in some cases is hilarious, BUT I had no problem understanding it and following it. It was useful, especially for someone who hasn't used a scope since 2003.

Are you looking to possibly buy one? I'm happy with mine. It came in handy earlier today when a PIC circuit I was working on wasn't working properly. I used the scope to get a visual on the output waveform and it helped me immensely.
By MichaelN
#118795
fll-freak wrote:...1) Are the ground clips on the probes isolated from the scopes earth ground? My current LeCroy is not isolated making picking arbitrary ground reference points impossible as it generates a short via the earth grounds.
I've never seen a scope that isolated the ground clips from the power supply "earth". The normal procedure is to use an isolation transformer on the power supply, but you need to be really careful since the ground clips could operate at dangerous voltages, depending on what you're measuring.

If you're using a scope with USB interface, you need to remember that the ground clips are at the same potential as the USB earth. This will be at the same potential as mains earth when you connect to a PC (at least on desktop PCs, and some laptops). You can get USB isolation devices if needed to get around this problem.
User avatar
By Chewie RFC
#118796
MichaelN wrote: I've never seen a scope that isolated the ground clips from the power supply "earth". The normal procedure is to use an isolation transformer on the power supply, but you need to be really careful since the ground clips could operate at dangerous voltages, depending on what you're measuring.

If you're using a scope with USB interface, you need to remember that the ground clips are at the same potential as the USB earth. This will be at the same potential as mains earth when you connect to a PC (at least on desktop PCs, and some laptops). You can get USB isolation devices if needed to get around this problem.
Good to know.
By fll-freak
#118802
In regards to ground clips being tied to earth ground. With other scopes I have used (Agilent/HP/Tek/LeCroy) other than my old Lecroy I have been able to clip the ground clip to locations other than earth ground as a reference. As an exampleI have cliped the ground to the V/2 point of a opamp to reference the other input and the output without haiving to either AC couple or deal with a large voltage bias.

But if I do this with my elderly Lecroy, the ground clip drags the V/2 reference to ground. (The V/2 being created from a voltage divider). And I get sparks if I clip to the 5 volt rail. And yet, I have never experienced these issues with much more newer and expensive scopes at work. If all scopes tie the probe tips to ground, then I am at a loss to understand how this could have worked.

I guess tomorrow at work I will play with my horibly expensive LeCroy ($250,000) scope and see how things are set up as well as the Tek lunch pail I have kicking around. Perhaps I have just been very lucky to have had isolated power supplies?!

This is what you get when a mechanical/aerospace engineer trained as a software engineer plays with electronics.

PS: I am indeed in the market for a new scope. My current boat anchor is just not up to some of the tasks and WAY to big to sit on my workbench.