Review: UNI-T UT81B Scopemeter

[mjlorton]

This is my initial review of the UNI-T UT81B Scopemeter

Review Index:

Introduction - 00:10 to 01:59
General look and feel - 02:00 to 06:20
Quality of probes - 06:20 to 07:43
Quality of the LCD display - 07:44 to 09:31
Specification of Scopemeter - 09:31 to 10:53
Accuracy of voltage, current and resistance reference tests - 10:54 to 14:23
Auto range, display resolution and update speed - 14:24 to 17:02
Continuity tester - 00:17:03 to 18:09
Scope demonstration - 18:10 to 24:20
Battery compartment and consumption test - 24:21 to 26:48
Final Conclusion - 26:49 to 28:54



Cheers,
Martin.

[Lightages]

Much better pace this time. For the time you took it would have been nice to see the inside and the input protection provided.

I have considered buying this unit a number of times but my experience with my UNI-T UT71E has left a bad taste in my mouth. Also, the lack of any on screen cursors for measuring things leaves me cold too.

[mjlorton]

Much better pace this time. For the time you took it would have been nice to see the inside and the input protection provided.

Thanks for the feedback.
I was hoping to get inside when I filmed the video but I could not figure out how to get it apart without damaging it. I will post a follow-up looking at the bits inside soon.

I have considered buying this unit a number of times but my experience with my UNI-T UT71E has left a bad taste in my mouth. Also, the lack of any on screen cursors for measuring things leaves me cold too.

This unit is certainly of no use for any half serious folks looking to do measurements. It may be of some value in giving a graphical representation of a signal for a novice getting into electronics.

Cheers,
Martin.

[saturation]

Many thanks for making this available.

It helps to expand the review of the scope capabilities if you conclude its the benefit of this device, yet spend far under 10% of the time discussing.

I'm not sure one can conclude that the scope is good value using a 600 Hz PWM signal and not demo key features you'd expect in a basic scope.

By examining upper limits of frequency response, signal quality and triggering, it would imply acceptability of its build quality, because RF signals will not tolerate sloppy construction very well, particularly without a BNC input jack.  The next thing of value is its robustness, and battery life as a scope.

As there are very few handheld DSO out there in this price range, finding one that can do what these other videos show for what it costs is, I think, great value.  They old reviews don't have video quality, but technically more revealing:

Looking at video signals on a monitor:




Scope review:

[rsjsouza]

IEEE mentioned this oscilloscope together with other two pocket-sized ones:

http://spectrum.ieee.org/geek-life/hands-on/pocket-oscilloscope-review-roundup/0

[saturation]

Great.  All 3 were also reviewed in the eevblog archives.   While there may be some pros and cons between the Uni-T and the Velleman, there is more consensus that the DSO Nano and its clones offer the least value for money.

IEEE mentioned this oscilloscope together with other two pocket-sized ones:

http://spectrum.ieee.org/geek-life/hands-on/pocket-oscilloscope-review-roundup/0

[Fraser]

An interesting review 

I was pleased to see the accuracy tests and that the meter was within spec.

As was stated, this is a compromise solution and is neither an amazing multimeter or DSO... I must state that it has proved to be a very useful instruments when out and about though. With regard to the LCD display.... for multimeter use I agree that a solid digit display is easier on the eye but the display is easily readable all the same. The comment about backlight performance is interesting as I personally have not had a problem with the LCD or the backlight and my Tektronix THS720 is about the same brightness level. I wonder if the brightness is limited in order to manage power consumption ? 

I also own the Velleman HPS140i and like it as a miniature DSO but the display is really too small for long periods of use. The UT81B has been fine for use exceeding 3 hours with no eye strain.

As a user of both Bench and portable DSO's I must agree that the UT81B is not a Bench DSO replacement, but rather a companion to such as it is that much more compact and mobile. Like many pieces of equipment that are very compact...they become a compromise solution but that does not mean they are compromised with regard to usefullness. I was very fortunate as an early adopter of this model as mine cost be only GBP90 ($137)delivered to the UK which I though great value for money. My kit included the DSO, BNC adapter, Oscilloscope probe, multimeter probes, PC cable, Croc clips, UT-12 Mains detector,  software CD, Mains PSU, batteries and decent travel case. It would appear that the price has risen and the accessories reduced 

I tested the UT-81B against the Velleman HPS-140i and the UNI-T wiped the floor with the HPS140i. The two may have the same sampling rate but the hardware is worlds apart with the UT-81B having a decent A/D converter and the HPS-140i having an A/D that was intended for use in TV's as a video digitiser ! I had stable waveform lock up to around 15MHz at the input and although aliasing must have been occurring, the display remained stable and clear. The HPS-140i display fell apart at around 4MHz ! Considering the HPS-140i is playing in the same market segment as the UT-81B, IMHO it isn't in the same league as the Uni-T offering. Still useful to own though 

I also own the following scope meters

Velleman HPS-10 (low sample rate)
Fluke PM97 (nice build but now a dated model)
Tektronix THS720(Nice  )
Tektronix THM560( dinky )
Velleman HPS-140i
Uni-T UTD-1025C (still under repair and improvement)

I very much like the Tektronix and Fluke offerings, but their original cost makes me wince ! Not a tool for the hobbyist or poorly paid techie !
The Uni-T UTD-1025C has also grabbed my attention since I bought it with a known fault that is now fixed. Its colour and decent enough build quality with a nice large and clear colour display mmmmmm    BUT that unit normally costs around GBP600 in the UK. In view of this, the UT-81B still makes a half decent portable DSO for the money. As I have stated in another thread...the potential purchaser has to ask themselves....Do I really need the small size ?...because you certainly don't get as many bangs for your buck when buying highly portable DSO's

[malagas_on_fire]

Hi there.
I'm a super fresh new user.
I've bought once in 2008 an UT81B and worked fine for graphing signals from microcontrollers ( Arduino, Microchip, NXP, etc) and then i sell it cause i stop the electronics and do some stuff on embedded Linux, becaming merely a software guy.

Now im going back to electronics and i have reorder a brand new uni-t 81B, which i kind like because its handy, simple to use and troubleshoot microcontrolers and now Linux SBC's. Its like a old Game Boy in terms of consumption, so i use recharchable batteries and 2000mA gives more or less 10 hours with low brightness ( 3) and contrast around 10.  However i don't remember what mode was the proper mode of the oscilloscope probe ( x1 or x10) for direct measuring. In x10 the signal it became attenuated with a probe model HP-3060 and the scope does not have option for the x1 and x10 modes... I should have take notes... Dumb me

Best Regards

[malagas_on_fire]

Ok the beginner's section is very good explained and it works directly with x1 mode  probe. Sorry