(Mini)oscilloscope advice

[quicknick]

Hello everyone,

Retro computing junkie here, feeling more and more the need for a simple and small oscilloscope. Kept postponing it, but after seeing this video I'm determined to pull the trigger so that 2022 doesn't find me oscilloscope-less.

So, what I expect from it? To be able to measure and display usual frequencies found on old PC boards (dunno if the unit from the above video passes this test, as it seems to display a sine wave instead of a (mostly) square one - maybe bandwidth is too limited?), and also to measure ripple (PSU rails, CPU/GPU/RAM VRM).

Handheld units as the one from above are strongly favored, but I'll consider other options too. Target price would be around 100 ($/EUR) but can go higher (200 max) if the features justify it (or if it's impossible to find what I need at target price).

Thanks!

[ataradov]

My advice - don't. Video editing does not show the frustration of trying to find a trace on that toy. Button interface for scopes never works (or at least I have not seen a good implementation that works).

Something like Hantek DSO2C10 or OWON SDS1102 are quite cheap (not as cheap as those handhelds, of course) and compact. They are also real tools with decent performance for the price.

[Doctorandus_P]

I agree with ataradov here.
It's a toy that has too many limitations to be used in a decent way and it will very likely end up in the bottom of a drawer because of it's limitations and because its so annoying to use.

Another review of this thing: EEVblog #1260 - $70 100MHz Oscilloscope?

This other Fnirksty is also too much rubbish to be worth looking at:
EEVblog #1317 - $140 2CH 100MHz Fnirsi Tablet Oscilloscope Review

That brand also makes a gadget in a "normal scope form factor", but if you take those other two as any indication then I fear the worst. That brand does not even try to make something useful, it just makes toys that look acceptable on paper and in shallow reviews.
I'd say just don't buy that brand. Maybe they are capable of making something decent in 10 years time.

All those mini scopes have a pretty cumbersome user interface.
If you really want such a small (and battery powered, which can be an advantage) scope, then have a look at:
Hantek 2D72 vs. OWON HD272S – Which Scopemeter is Better?


Those do have two channels, so you can compare input and output of a circuit to each other.
They are also a bit less cheap, but the price difference between those and a scope in a "normal form factor" is becoming quite small, and those bigger boxes have a much better user interface.

[quicknick]

Thank you both!
As usual, one look down the rabbit hole, and suddenly I realize how little I know on the subject!
I started by watching the 2D72 vs. OWON HD272S video, at the end I was quite convinced about the Owon, but after that went and watched a video on the SDS1102 and boy, does a "proper" oscilloscope make those handhelds look like toys...

A comment at the end of the handhelds review got me worried: "Also minimum v/div is too high making it impossible for low voltage or noise measurements." - not sure if I wholly understand, but does this make them unsuitable for measuring ripple/noise on power rails? Also, what is the importance of protocol decoding?

Another issue (although it shouldn't be a problems in most of the measurements I'll need to take) - am I right in assuming that the ground of the probe is connected to the safety earth in mains powered scopes?

[james_s]

The little handheld scopes are essentially just toys. They are marginally better than no scope at all but I would not want to have to get by with one. IMO you are better off saving your money up until you can afford something like a Rigol or other budget DSO, they are larger than handheld but still quite compact. If that is really too much of a stretch then you could look for an older used scope and pick up one of those.

There is a saying that applies here "buy cheap, buy twice", I think if you buy a cheap handheld you will quickly outgrow it and decide you need something better, hence it is cheaper in the long run to spend a bit more.

It might help to know what you actually intend to accomplish with the scope though. "Measure and display waveforms on old PC boards" could mean different things. It sounds like perhaps all you want is a toy? If that's the case then sure, you will be able to see waveforms, but what's that going to do for you? You may be better off learning more about oscilloscopes, how they are used and for what applications before you spend any money. Having a scope without having a solid understanding of what to do with it is not really going to help you much, unless you just want to play around.

[ataradov]

A comment at the end of the handhelds review got me worried: "Also minimum v/div is too high making it impossible for low voltage or noise measurements." - not sure if I wholly understand, but does this make them unsuitable for measuring ripple/noise on power rails?

On the chapos you mostly measure weather in Africa on low v/div settings anyway.

SDS1102 has 50 mV/div lowest setting. It is not ideal, but usable for ripple that may affect digital electronics.

Also, what is the importance of protocol decoding?

Not at all, especially on low end scopes. On the toy scopes it is even bigger joke. Get a cheap USB logic analyzer and your life would be instantly better.

Another issue (although it shouldn't be a problems in most of the measurements I'll need to take) - am I right in assuming that the ground of the probe is connected to the safety earth in mains powered scopes?

Yes, in most cases.

[Zero999]

If you need portability, get the OWON DS7102V, with the battery option. It's more expensive, but the nice big screen is worth it. Note that it shouldn't be used above 25VAC, or 60VDC, when run of the battery and unearthed. Never use on the mains.

[dophuc]

I have a handheld oscilloscope (OWON HDS242, 2CH/ 40Mhz + DDM 20,000 counts) and a 4CH oscilloscope (Siglent SDS 1104X-E). I bought Owon for only about $120 and I really like it. The oscilloscope function is simple but quite useful. DDM function can measure resistors, diodes, capacitors...