Budget 3in1 - 120MHz Oscilloscope Multimeter Signal Generator

[Demon]

Has anyone tried out these budget 3in1 meters from China?

My DMM is getting old, and my 2 used Tektronix are heavy, bulky and honestly showing their age.

https://www.aliexpress.com/item/1005005933508541.html

[Ioannis]

Looks like a dream.

But what about support if anything goes wrong?

From my little experience on chinese multimetrs I can say that they lack any good circuit design regarding creeping distaces, fuses protection (of the instrument and the user)).

Even UNI-T that seems better from the rest cheapies have these problems.

I'd preffer to find a deal on Ebay maybe.

Ioannis

[HenrikOlsson]

This is one of those things where the answers is "It depends", and it depends a LOT.
What's your usecase? On the hobby bench for the odd PIC project looking at 3.3V and 5V logic signals or in your toolbox to do troubleshooting around the house? In the first case it might work, in the second I would not trust it without some initial safety tests (which might destroy it).

It says it can measure up to 750V but there's no CAT rating on it, not even a fake one (which I suppose is better than a fake one). Will it survive or explode in your hand if you stick the probes in the wall outlet with the meter set to measure resistance - for example. If that's not something you'll ever do then obviously it might not be an issue.

It does not seem to be battery operated meaning it's use as a general purpose multimeter is limited. Also, you'd need to investigate and understand how the powersupply is connected realtive to both the COM terminal on the multimeter input and the ground of the oscilloscope inputs. Are they all the same? Then, if the powersupply is floating and you measure 250V with the multimeter inputs it's possible that you can have 250V (relative to ground) present on the exposed BNC connectors.

Again, all this might not be a problem for you but it's something that has to be kept in mind.

Although 250Ms/s meets the Nyquist theorem for the rated bandwidth of 120MHz you have to keep in mind that it's for pure sine wave signals. For more complex waveforms like squarewaves and pulses I would not expect that thing to work remotely accurately above 25MHz. And with two channels turned on it (as often the case on digital scopes) the ADC is multiplexed between channels so the effective sample rate for each channel is "only" 125Ms/s.

For an oscilloscope a 3.2" screen is really quite small. Not something I would want to use on a daily basis.

With all that said you DO get a hell of a lot for $100 these days.

[Ioannis]

I totally agree with your points.

Indeed CAT is not mentioned and the UNI-T's mark their meter I guess with a very optimistic view...

So, yeah, better not to fake mark it and be aware of that. And cautious too.

I 've done some stupid mistakes, like ac measurements on ohms range with my Fluke meter. Needless to say it did not felt anything. But you 'd expect that with such a price tag, right?

Yes, it is impressive what you get with same amount of money now. I don't believe what 300-350 USD buy in Oscilloscopes! Only in my dreams when I was young!

Ioannis

[Ioannis]

The LCD is too small for my eyes.

I noticed now that on the front panel it says that 10A is not fused.

Ioannis

[richard]

it has a 2500 mAh battery, so it should be portable enough
but what does menual do

[Ioannis]

Something with a menu maybe?

Ioannis

[HenrikOlsson]

Or "Manual".
Either is in opposite to automatic or, perhaps, display the manual on the screen. Or something completely unrelated to both Menu and Manual....

Ah, so it does have a battery, then it makes more sense. I'm surprised they didn't put that in the banner specs.

[Demon]

Henrik, I have absolutely no plans to shove that thing into 110/220VAC. This is for 5VDC, and eventually lower voltages.

As for the speed, it's going to be used exclusively with 18F PIC, and only one probe at a time. But it is good to know that they most likely share the same circuit.

I might keep on using my Tektronix (100 MHz) and HK Precision (60MHz) scopes. I just have to make a small shelf to elevate my mini-CNC 8-10 inches. Those monsters are just so huge, and my workbench is not wide to have either one up, while doing soldering and stuff like that.

Might start by changing the battery on my DMM and see if that fixes the inconsistent readings when checking continuity.

Those chinesium meters do look tempting though. I think I saw a no-questions-asked return policy on AliExpress (have to check).

And a huge thanks for all those comments.

[Demon]

Holy crap! I just checked the wikipedia for the 466, and saw the prices:

Year 1986
Catalog Price $7,560
In 2023 Dollars $21,200

Wow! I got these off eBay many years ago for maybe under $250.

[HenrikOlsson]

Yeah, once upon a time those boat anchors were the ducks guts. When I got into the electronics hobby in the early nineties I could only dream of having an oscilloscope, even the cheapest/simplest 20MHz ones were way out my teenage budget.
Now on my shelf I have a Tektronix 2465B (4 channel, 400MHz) which by many is considered to be one of the best "portable" scopes ever built. Price in 1990 $13k or about $31k in todays money. I payed a few hundred USD for it 10 years or so ago.

I basically never use the 2465B though. Whenever I need a scope I go for one of the digital. What you can get in a scope for a few hundred bucks today is just increadible.

[Jerson]

I am a fan of such devices. I own a DSO203 (2ana+2dig channel pocket DSO) which works well till about 2MHz and is suitable for my kind of work with PIC and other microcontrollers. I cannot do any analog / accuracy needed type things with it, but allows me to scope signals for shape and amplitude. It too has a signal generator built in. You may argue, that it is a toy. Yes, indeed! However, the convenience is unbeatable when you can carry your DSO in your pocket. Another speciality of this scope is that it is FOSS. I have contributed to the source code in a small way. Multiple versions of the firmware are online and you can choose which one suits your taste.

Another mid-range between pocket and desktop scope I own is the JDS2022A from jinhan. This runs 20MHz analog bandwidth. However, it is a power hog as it uses relays for selections.

This budget 3-in-1 scope looks very tempting except they don't ship to India anymore. Else, I would certainly buy this as another tool in my cupboard.

Counter argument would be - with so many PC scopes available, why would anyone buy such a device. Well, you cannot beat the convenience of having a self-contained DSO with battery power for one.

Anyway, thanks for asking this question. Got me interested in this.

[Demon]

Holy moly!

https://www.aliexpress.com/item/1005006329135606.html


The western world had better get their proverbial butts in gear. China is coming at ridiculous speed.

I'm most likely going to get one of these, probably the DOS1104:
- 100-349 MHz
- 7 inch screen
- 4 channels with probes

I don't know enough to comment on the other specs, but this is way more practical to use than my ginormous boat anchor of a BK Precision scope.

We are being seriously left in the dust by China.

[Ioannis]

Please don't waste your money on unknown or no-name brands.

https://www.aliexpress.com/item/1005...Cquery_from%3A

Not even close to Han...something...

I can understand the price difference, but Rigol and Siglent has done miracles on Osciloscopes.

Ioannis