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