I’m a hobbyist looking into buying my first oscilloscope. I’m NOT looking for a brand recommendation or price war. Rather, I'm hoping to get a better understanding of what features I should be looking at in my product research.

Typically, my work falls into these categories:

• Microcontroller circuits and pre-built boards (Arduino, mostly) running clocks from 16 MHz to 32 MHz
• Sound generator circuits (discrete and op-amp) and pre-built boards (for WAV/MP3 on SD cards), and amplifiers
• Small DC motor controllers (12 V, 1/2 amp or so) with H bridge and PWM control (500-2000 Hz)

An example project I’m in the design phase of is a music box with a digital selector for choosing songs to play and a variable speed motor for turning a miniature carousel. I'd like to be able to test the audio signal quality before and after the amplifier, look for glitches in the motor PWM signal, and verify the I2C line between controllers, that sort of thing.

Based on my understanding of attenuation in scopes, I think a 100 MHz scope is likely to suit my needs, although a nagging voice in my head keeps saying "more is better!". I think two channels would probably be good, but I’m planning to go with four just to give myself a little room for growth. I’m definitely looking at ones with at least the option of adding some digital channels from monitoring I2C and SPI communication between different controllers.

Am I in the right ballpark with those numbers and what I want to do? What other features, tolerances, or gotchas should I pay attention to while researching different scopes? Any and all advice would be greatly appreciated.

 

Welcome to AAC!

You will receive 12 different recommendations from 12 different people.

1) The first consideration is budget. You can buy a scope for US$50 or $5000.
2) New or used.
3) Analog or digital.

If you are on a budget, you can find a good brand name analog scope for US$50 to $100.
When getting a used scope, consider the cost of quality probes. Your scope is only as good as the probe. A pair of probes can cost an additional $50.

You can buy an excellent digital scope for under $400 (that includes two oscilloscope probes).
So, for a hobbyist, you can set a max budget at $500.

More is better? Maybe, but not always.
You want a scope bandwidth to be no lower than 50MHz.
100MHz is fine for just about everything you will need.
You don't need four channels.

Here is the bottom line - two options:
1) A used 2-channel analog scope US$50-$100, 50MHz to 100MHz with 1X & 10X probes.
2) A new 60, 100, or 200MHz digital 2-channel colour display for under US$500 with probes included.

 

Welcome to AAC!

You will receive 12 different recommendations from 12 different people.

1) The first consideration is budget. You can buy a scope for US$50 or $5000.
2) New or used.
3) Analog or digital.

Thank you, it's nice to be here.

I'm not sure about budget yet, which is why I'm trying to understand what to look for. I don't want to bust the bank on a scope that is more than I need, and I don't want something that just won't do the job or is unreliable. As a tangential example, my first (and so far only) MM is a Fluke 115; it had the features and reliability I was looking for, but not the be-all-and-end-all-check-your-circuit-and-rub-your-feet super tool that I could have dropped money on.

I've been looking at new scopes so I have a warranty, and digital scopes mostly because I feel more at home with digital. I've been leaning toward entry level scopes, but price isn't the main motivator. If there's a scope feature or precision that will keep me from pulling my hair out, I'm willing to pay more for it. I'm mostly a little bewildered at all the options at this point.

 

I sense that you are considering Rigol DSO1054Z, which you can now buy with most options enabled. 50MHz is probably more than you need for your applications, but the scope is easily upgradable to 100MHz should you want a little more. (you actually get 60Mhz or 120Mhz in real life). Scope probes handle more than 100MHz whichever version you buy.

If my guess is right, then you get my vote. I have used mine with micro controllers for years and it is more than adequate. The bangs per buck figure is good too.

Do not make the mistake of buying the Logic Analyser and/or Signal Generator options. They are poor substitutes for separate LA and SigGen units which can be bought with the money saved and will be far superior.

Analogue scopes are not suited for micro controller use IMHO. DSO is pretty much a must.

Cheaper options may damage you hair

 

I sense that you are considering Rigol DSO1054Z, which you can now buy with most options enabled.

If my guess is right, then you get my vote. I have used mine with micro controllers for years and it is more than adequate. The bangs per buck figure is good too.

Do not make the mistake of buying the Logic Analyser and/or Signal Generator options. They are poor substitutes for separate LA and SigGen units which can be bought with the money saved and will be far superior.

Analogue scopes are not suited for micro controller use IMHO. DSO is pretty much a must.

That's good information about the additional features, and digital/analog comparison, thank you very much.

I've looked at some Rigol models as well as a couple of Siglent models (1104 and 1202 mostly). I've also looked at the Tektronix MSO2014B, but I don't know how to tell what the difference in price would get me.

 

Hello,

Perhaps @Wuerstchenhund can tel you more about the differences of the mentioned scopes.

Bertus

 

.. or check out eevblog forum.

It is THE go-to site for test equipment.

... but be warned.... out of 12 opinions, you will receive 10 Rigol DSO1054Z recommendations, 1 Siglent, 1 Tek recommendation (speculation not fact)

Tek is a great brand, but best suited to professional use. The affordable models are poor spec compared to hobby brands (but probably good enough for your requirements).

and by the way... MCU clock frequency is rarely an important factor. You will mostly be concerned with SPI, I2C or similar clock rates, which currently rarely exceed 10MHz square wave. 50MHz scope is probably just enough to get a fair impression of 10MHz square wave fidelity, but might struggle. Most MCU projects use communication at 1 MHz or less. If all else fails - debug your project at, say, 1MHz communication rate and then increase once you have it working.

 

That's good information about the additional features, and digital/analog comparison, thank you very much.

I've looked at some Rigol models as well as a couple of Siglent models (1104 and 1202 mostly). I've also looked at the Tektronix MSO2014B, but I don't know how to tell what the difference in price would get me.

I've got a MSO2000B scope. Nice well made scope with all the MSO extra modules but it can be slow and clunky at times plus you're buying a name.

uC signal debugging.

Keysight DSOX1102G on top, same signal.

MSO2000B logic analyzer functionality

 

Thanks very much, everyone... that's given me several more ideas to add to my list for what to look for.

 

For me, I very much need fast refresh rate with segmented memory for uC applications. I'll let you google these terms if you're not sure what they are. This allows for seeing many sequential serial communications. Serial triggering is a must as well as serial decode. For you I'd at least get SPI, I2C, and UART decode. If you can afford it and think you might need it in the future, USB and CAN decode is also helpful.

4 channels is a must for spi debugging. However, you don't need an analog signal. A logic analyzer will usually work. However, I prefer to have a MSO in either a 4+16 or 4+8 configuration (2+8 would be a minimum I'd think). This gives ultimate flexibility in small form factor. I will admit that you don't get some of the perks of a true logic analyzer, but I have honestly found the need for a true logic analyzer to be ever diminishing as technology advances.

 

4 channels is a must for spi debugging. However, you don't need an analog signal. A logic analyzer will usually work. However, I prefer to have a MSO in either a 4+16 or 4+8 configuration (2+8 would be a minimum I'd think). This gives ultimate flexibility in small form factor. I will admit that you don't get some of the perks of a true logic analyzer, but I have honestly found the need for a true logic analyzer to be ever diminishing as technology advances.

+1

SPI debugging on the Tek MSO.

It's nice to have a fast analog scope at times just to see serial bus loading effects on the signals at higher speeds.

Tek 2465A

 

For me, I very much need fast refresh rate with segmented memory for uC applications. I'll let you google these terms if you're not sure what they are. This allows for seeing many sequential serial communications. Serial triggering is a must as well as serial decode. For you I'd at least get SPI, I2C, and UART decode. If you can afford it and think you might need it in the future, USB and CAN decode is also helpful.

That's good to think about, thank you... I've been thinking about the value of seeing digital waveforms, but I haven't thought about decoding. Also, off to research those terms.

It's nice to have a fast analog scope at times just to see serial bus loading effects on the signals at higher speeds.

Ah, also something I hadn't thought of. Thanks!

 

You got a lot of recommendations already so I'll keep this short:

- The Rigol DS1054z is still a killer bargain for its price, especially since it can be unlocked. It's drawbacks are the somewhat slow platform (which shows in a sluggish UI and a very limited FFT with 16kpts only), and the fact that serial decode is done on screen data so if your data word/packet goes beyond the screen then then the scope will decode garbage.

- Siglent's SDS1000X-E scopes are a bit more expensive, however they are built on a faster platform than the Rigol and offer better performance. They can do FFTs up to 1Mpts and as far as I know use data in the sample memory for decode so the decoder doesn't fall over if you zoom into the signal.

- Both the Rigol DS1054z and the Siglent SDS1000X-E Series are great beginner scopes, and especially the Siglent has some capability should your needs grow in the future.

- Forget Tektronix. Seriously, ignore them. They had their heydays during the analog scope era but their digital scopes are all between 'poor' and 'utter crap', and the only people that buy them are educational facilities like colleges, mostly because the staff there knows the brand from the analog days and because Tek gives them huge incentives as they are pretty much their last remaining customers. Tek DSOs are slow, they tend to crash or lock up if they have to do anything demanding (like decoding a signal or FFT), and vastly overpriced. The UI on scopes like the MDO Series is generally horrible and has clearly designed by someone who must have a certain hatred for humans. These days, there's hardly any brand with worse scopes.

- Forget analog scopes, unless you want to become a curator for antiques.

 

- Forget Tektronix. Seriously, ignore them. They had their heydays during the analog scope era but their digital scopes are all between 'poor' and 'utter crap', and the only people that buy them are educational facilities like colleges, mostly because the staff there knows the brand from the analog days and because Tek gives them huge incentives as they are pretty much their last remaining customers. Tek DSOs are slow, they tend to crash or lock up if they have to do anything demanding (like decoding a signal or FFT), and vastly overpriced. The UI on scopes like the MDO Series is generally horrible and has clearly designed by someone who must have a certain hatred for humans. These days, there's hardly any brand with worse scopes.

- Forget analog scopes, unless you want to become a curator for antiques.

That's good to know (but sad to hear) about Tektronix. I've seen that in other industries I've been involved with, where over time a lesser product gets sold with with old brand name.

I may get an analog scope sometime, maybe a used one for cheap just to play with. I'm a (moderately) old guy so an old 'scope seems appropriate. :-D

I'm still a bit bewildered by all of the possible features in a scope, but I think it's better to dive in and get some experience before I get in too deep (that is, keep it under $1000 USD) and walk before I run.

Thanks for the input!

 

Thanks very much, everyone... that's given me several more ideas to add to my list for what to look for.

Let me just say that the performance and value of modern digital oscilloscopes is amazing....it's almost impossible to go wrong. The first digital oscilloscope I ever encountered was a LeCroy about 22 years ago at UCLA. It was a $45,000 scope at the time. My new Tektronics DSO does everything that LeCroy did...and more....for $450.......1% of the LeCroy.

 

That's good to know (but sad to hear) about Tektronix. I've seen that in other industries I've been involved with, where over time a lesser product gets sold with with old brand name.

Yes, it's a shame. We had some evaluation versions of their new MSO5 and MSO6, and besides the braindead UI (switching off a channel by dragging it into the recycle bin?) they were still slow and full of bugs. When Tek's new entry-level scope TBS2000 came out the software for it wasn't even finished (there were buttons which didn't do anything).

I may get an analog scope sometime, maybe a used one for cheap just to play with. I'm a (moderately) old guy so an old 'scope seems appropriate. :-D

Sure, if it's for playing/interest, why not. But be careful, despite common belief an analog scope isn't a good learning tool to prepare you how to handle a digital scope correctly. Also, it won't show you anything that you can't get from a decent DSO. And this is besides the fact that analog scopes are dead and have been so for a while (and despite technology becoming ever more complex since), and are not coming back.

 

Danahar, the parent of Tek and Keithley and Fluke just ruins the old experience. I think I'm right anyway.

 

Before we look at features, you really need to understand basics that are universal irregardless of scope brand. If you don't start with these basics, you could wind up regretting it, or not having a scope to do what you need.

SAMPLE RATE
=================
An oscilloscope does just one thing- it looks at voltage levels so many times per second. In order for you to capture enough samples, your scope should be able to capture at least 5 data points for the fastest signal you ever intend to examine.

Let's look at a 32MHz MCU, just as an example. Brand doesn't matter- clockrate is all you're interested in.

32MHz means, that the MCU has a hearbeat pulse every 1/32000000th of a second. How fast is that? Well, that's 0.00000003125 seconds per heartbeat/pulse, or 31.25ns per pulse. Divide that by 5, at a minimum so the scope can read at least 5 samples to display that waveform with some cleanness- and that means the scope should be able to sample at atleast 6.25ns-- or 160MHz.

I _strongly_ recommend atleast 1Gigasample/second, and 2 if you can find scope and afford it.

Don't be afraid of purchasing an old scope either- Tektronics, Agilent, Lucent, all made fine scopes in their day. Finding a TDS360 for $200.00 could give you all the scope you ever need.

TRACES
=========
You want at least 2 traces. 3 or 4 is better, but at least 2. Having two traces allows you to monitor one signal and compare it against another-- which is invaluable.

PROBES
=========
Now we get down to the least thought of (usually), yet most vital part of your oscilloscope- the probes. The reason being: They are the last-mile between your scope and the signal- and how they interpret, load, or alter the signal is important to understand. I kid you not when I say that it is possible for your probes to cost more than the oscilloscope itself. You want at least 10x probes - that value is an attenuation or 'scaling' factor. Make sure of your price of probes, and if you can get a better deal on an extra pair at the time you purchase your scope- get them then, so you have a back up.

Lastly, talk to someone near you who knows how to use a scope properly. It is vital that you understand how your scope grounds, and how it isolates itself. If not, you could connect your probes and their individual grounds in such a way (with an A/C signal for example), and create a short right through your scope, damaging probe, scope, or both. This can happen easier than you think. _always_ be cognizant of exactly what the path of current is through your scope so as to avoid making it a path to ground.

Rigol seems to make fine products as well, I have several for other purposes. I was fortunate enough to acquire Tektronix equipment during the telecom flood of equipment on the market several years ago, at an incredibly low price.

I also recommend a scope that can handle analog with digital capture capabilities.

Good luck in your search! We look forward to hearing about what you acquire!

 

Let me just say that the performance and value of modern digital oscilloscopes is amazing....it's almost impossible to go wrong. The first digital oscilloscope I ever encountered was a LeCroy about 22 years ago at UCLA. It was a $45,000 scope at the time. My new Tektronics DSO does everything that LeCroy did...and more....for $450.......1% of the LeCroy.

I have a TD360 DSO (Tektronix) as my favorite scope- I have not found anything in working with electronics that it hasn't been able to handle for me just fine. I got mine for $350, including 3 probes.

 

+1

SPI debugging on the Tek MSO.

It's nice to have a fast analog scope at times just to see serial bus loading effects on the signals at higher speeds.

Tek 2465A

This is one of those areas where people say digital is better, but the main difference is that with analog, you see the actual waveform, not 'cleaned up'. And it is incredibly valuable to be able to see this because this alone can help someone solve signal problems because the waveform doesn't lie.

I have nothing against new digital, but... I'd hate to be entirely without analog for the reason above. I can see ringing, I can see capacitor and inductor behavior with the analog. I don't know how much of that might be lost with an 'all digital' scope.