Portable Oscilloscopes List (cheap)

[awakephd]

I recently got a Zeewei DSO3D12 to replace a DSO154 - main reason for replacing the latter was that I accidentally cracked its screen.

If you are familiar with the DSO154, the DSO3D12 will feel very similar in terms of UI - even though it has quite a few more buttons to control its operation. The latter is a good thing, I'd say, increasing the convenience of changing time base or vertical scale in particular. The one thing that was mildly annoying in the UI is how to move up and down in the menu - annoying only because I could find absolutely nothing in the manual to tell how to do it. I had to try various buttons until I finally realized that it treats the column of buttons next to the display as "soft buttons" to select each menu section. Within the menu section, the arrow buttons and OK button work as expected / much like the DSO154.

Is it worth the extra $50? Well ... jury is still out on that. I mostly just wanted something portable and battery powered for times when those attributes are needed. Dual channels is definitely a plus for the uses I have in mind for it. An actual case feels like it might be less likely to succumb to damage than the DSO154 proved to be. All in all, I have no buyer's remorse; it's just hard to get as excited about this for $80 when I had something that felt and looked very similar for $30 - albeit only 1 channel, smaller screen, and lower specs.

[Fungus]

Just watching the Zeeweii videos in this post:
https://www.eevblog.com/forum/testgear/another-dsodmm-zeeweii-dso3d12-claimed-120mhz250msps/msg5274556/#msg5274556

Imagine you're starting out from zero...  it gets you a lot of capability for $100 bucks (multimeter+scope+siggen).

I like the display of where to put the multimeter cables:

[Fungus]

If you are familiar with the DSO154, the DSO3D12 will feel very similar in terms of UI - even though it has quite a few more buttons to control its operation.

Yep, menu looks almost identical, but much easier to navigate.

Setting timebase and vertical is much easier, too - dedicated buttons!

Is it worth the extra $50? Well ... jury is still out on that. I mostly just wanted something portable and battery powered for times when those attributes are needed. Dual channels is definitely a plus for the uses I have in mind for it.

Single channel is a big limitation.

This one has multimeter, too. If I could leave the meter out of my case then it could be a win in terms of space. I'll have to make a cardboard model and see the real size. 

I'm tempted.

I'll sleep on it for a few days though... 

[awakephd]

Setting timebase and vertical is much easier, too - dedicated buttons!

Yes, that is one of the best features / most intuitive parts of the design.

I like the display of where to put the multimeter cables:

Agreed, they did this very well. Even better would be a single set of inputs that are internally switched, but let's not get greedy ...

[BillyO]

Even better would be a single set of inputs that are internally switched, but let's not get greedy ...

Bad idea.  Accidently making a poor a mode choice while connected to a strong voltage source or a sensitive circuit could cause myriad problems.  They don't keep inputs separate to reduce cost or make things easier for themselves, they do it for (what should be) obvious safety reasons.  You may have too much experience with cheap "Smart" meters that do not have current ranges.

[awakephd]

You may have too much experience with cheap "Smart" meters that do not have current ranges.

BillyO, you are giving me far too much credit. In my case, it is a matter of far too little experience in general. Thanks for helping me to see the advantage of the separate inputs!

[Fungus]

Even better would be a single set of inputs that are internally switched, but let's not get greedy ...

Current inputs are low resistance (passthrough) and have fuses*, that's why they make them separate.

You could do it with shared jacks but you'd need to add internal relays and all sorts of stuff and any bad range selection would blow your fuses.

(*) Yeah, I know the 10A range on this particular meter is "unfused".

[BillyO]

BillyO, you are giving me far too much credit.

I like to give people the benefit of the doubt. 

[BillyO]

You could do it with shared jacks but you'd need to add internal relays and all sorts of stuff and any bad range selection would blow your fuses.

Except in the case where your meter was hooked up to a small 50ma diode, or tiny transistor or.. something else that would not blow a 600ma fuse before giving it's own life to make yours is more interesting.

Also, even if the meter was smart enough to put a 10A fuse in line (not hard to do with a big, brawny relay) when in that mode, it better well be a darn good fuse if it suddenly finds itself across the 415v mains feed in a breaker panel in the UK.  Or some other suitably contrived situation (which do occur occasionally).

[MathWizard]

I'm interested in something like the FNIRSI 2C53T, as a cheap handheld DMM+DSO (the basic AWG is a bonus too, pretty handy for basic audio repair). I gather most of these cheap devices aren't up to the safety ratings, they might advertise.

But has anyone modded these to upgrade the input protections? There's not much room in some of them, but others there is.

I have 1 of the early DSO138's, (besides my expensive gear) and w/o a case, it was always pretty annoying, and I had no reason to use it.

But for a cheap handheld, that's not as expensive as the OWON HDS2000's, how are these regarded ? I'd say for my hobby low-voltage stuff, this should be fine as a field meter.

Looking at this video, I think the UI is ok, and it seems ok for upto a 10MHz square-wave, but yeah a bit faster would be nice, for looking at MCU's/etc.

This has some FFT function, but it hasn't been worked on enough, or they ran out of room to store the program. Going by that video anyways.




I'd really like to see Mike Smith (I hope I got that right, maybe it's Joe Smith) hook this up to his high voltage machines, and see what happens. If I get 1 of these, it would be nice to upgrade the input protections, for household levels, if it's really lacking it.

[Fungus]

I gather most of these cheap devices aren't up to the safety ratings, they might advertise.

But has anyone modded these to upgrade the input protections?

If you're regularly going into life-or-death situations then get a suitable device.

If not, get a FNIRSI.

[MathWizard]

No the worst thing I might look at would be a LED/LCD TV or Stereo, maybe a dishwasher. So how bad could their DMM protections really be, has anyone done a real teardown ?



Well that's an older or lesser version I think.


But how hard would it be to put proper protections on a PCB, and fit it in there somehow. IDK the clearances required for the various voltages, or how much the parts would be, I'm guessing not much. I remember a video of Mr.Smith upgrading one of the Uni-T DMM's to a very high level, I'll have to find that again.

[tunk]

Another of the cheap ones, PDS833, 1MHz/8.3MSps.
From around US$25, but for a similar price, you can
get a much better Zeeweii DSO154PRO.
https://www.aliexpress.com/item/1005008261777874.html

[Peabody]

+1 on the DSO154Pro.  I don't know about the safety features, but it appears to be head and shoulders above the other single-channel scopes, particularly at the price.  Apparently it will do a real 18MHz, and you can even zoom in.  :-)

[Fungus]

Zeeweii is where it's at for 'scopes.

FNIRSI is better at power supplies.