oscilloscopes what to look for?

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Hi guys, I would like to buy an oscilloscope but I really don't know what to look for.

I don't want to spend a lot of money on things I will never use but at the same time I don't want to buy something that I will have to replace in 6 months because it does not do what I need it to do.

I exclusively tinker around with AVR chips as a hobby and would like to be able to troubleshoot communication problems between devices more then anything.

Any input would be really appreciated.

I'm not a cartoon character but I play one in real life.

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A search in this forum (General Electronics) and in the OffTopic forum will bring up several recent threads on this subject.
Read those first, think about how much money you want to spend. That will narrow things down a lot. And if still are in doubt what to buy, you're more than welcome to come back here with the results of your investigation.

Nard

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tessa and Tina, You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

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Tektronix TDS2022B and TDS2024B are good value for money, but are a bit out of reach for hobbyists. :( But check those out anyway and compare then with the rest to see how the other, cheaper offerings match up. See what you're willing to give up, so to speak.

Good rule of thumb: the bandwidth you need is about 10 times the frequency of the highest frequency pulse waveform that you will encounter. Most AVRs run at 20 MHz tops, so 200 MHz scope if you want to see the clock, but since not many people want to see the clock itself, the port pins will toggle at a maximum rate that is half that, so even a 100 MHz scope will do.

If you think education is expensive, try ignorance.

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FWIW: emuler, I have a TDS2022 (not the B-version unfortunately), and frankly: I am not impressed with it. Since the buffer is quite small ( 8k IIRC ), spikes and glitches are hard to dispaly: the trigger catches them, but they are not always displayed. I still have the old analog scope to catch these naughty problems.

For Qema: check out Rigol: more value for money, and if the budget is tight, consider a second hand analog scope. Like emuler said, a 100MHz is fine. Mine is just 50MHz, and good enough for AVR-things. Just remember that what you see is limited in bandwidth.
Probes are crucial btw ...

Nard

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tessa and Tina, You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

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If you're mainly interested in troubleshooting digital communication, why not consider a logic analyzer? I don't actually own one of these yet, but the Saleae Logic has a gorgeous interface, and will tuck away nicely when not in use:

http://www.saleae.com/logic/

And for $150, you're coming in well under the price even of most used analog scopes. If it's all you need, it may be a viable option.

Michael

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Quote:

the Saleae Logic
has a sampling rate of only 24 MHz.

But leaving this aside, an oscilloscope is a "universal" measurement instrument, a logic analyser is a highly specialized instrument. If budget is tight and I would have to chose between an oscilloscope and a logic analyser, even for digital work only, I would seriously entertain an oscilloscope.

Stealing Proteus doesn't make you an engineer.

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crwper wrote:
If you're mainly interested in troubleshooting digital communication, why not consider a logic analyzer? I don't actually own one of these yet, but the Saleae Logic has a gorgeous interface, and will tuck away nicely when not in use:

http://www.saleae.com/logic/

And for $150, you're coming in well under the price even of most used analog scopes. If it's all you need, it may be a viable option.

Michael

There are things a 24MHz PC based logic analyzer limited to 5V signals can see, and there are things a standalone 100MHz oscilloscope can see. They are for completely different things.

btw, I am still waiting for my Logic to arrive..

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Jepael wrote:
btw, I am still waiting for my Logic to arrive..

I'm attracted to the simplicity of the Logic's interface, and have been thinking of picking one up. How long have you been waiting?

Michael

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Ive had my logic for nearly a year now and its been nothing but excellent working with signal voltages 2.7-5V, I have not tried it on anything else. The long ass(thats a metric unit of ass) usb cable that it comes with it great too as it makes the restriction of being attached to a computer (desktop mostly) a non issue.

The software is great but my only issue is that i can not reliably maintain sampling speeds Near or over 10M. This could be due to it being used on my laptop which is sure to have a bunch of internal devices on the same bus as well. The port it is connected to does make a difference too. It would be nice is Saleae came up with an option that would disable the data capture on unused channels to increase the bandwidth. With streaming devices like these the capture rates are all going to be restricted across all devices. I have used a USD dx at a job and had similar experiences with the USB connection being the limiting factor for capture.

Running the logic on a VM using virtual box on ubuntu host speeds cap out a lot lower at 1M.

PS the case the logic comes in is also a nice extra especially at the 150 price point. It leaves enough room for an ftdi board and a serial to usb adapter.

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Hi,

This guy speaks about oscilloscopes(and other stuff)

http://www.eevblog.com/page/16/

regards

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Quote:
I exclusively tinker around with AVR chips as a hobby and would like to be able to troubleshoot communication problems between devices more then anything.

As Nard mentioned, check out Rigol digital scopes.

As budget is an issue, I would buy a digital scope before I would buy an analog scope these days. This is especially true to use it to look at communications between devices, sensors, etc.

You will want at least TWO channels. There are some low cost 1 channel scopes out there, avoid them. Much of trouble shooting and debugging involves timimg relationships between several signals. Additionally, one can often set a bit on one channel to trigger the scope trace while watching the other channel with the signal of interest.

The number of Samples per Second is also an important parameter, the more the better.

Included software to print out a scope display is useful for including in one's project documentation, or for school reports, or for posting here, etc.

For many users, but probably not for benchtop hobbists, the isolation rating for the channels can be important.

JC

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I bought a Rigol 100 MHz scope for a little over $700, I'm happy with it.

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Rigol is good value, I have the 50mhz scope for ~$450. the 1m sample buffer was very useful for capturing a single trigger event.

Some Low end Aiglent scopes are actually rebranded Rigols.

The layout of the controls on my Rigol unit is very well done, everything is logically where you think it should be. I have not read the manual and I got 95% of the functions working.