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EEVblog 1378 - NEW Uni-T UT61E+ Multimeter

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HKJ:

--- Quote from: Trader on March 19, 2021, 04:52:41 pm ---A good (chinese) probe has resistance around 0.3 Ohm.

ProbeMaster around 0.25 Ohm

--- End quote ---

I would expect about 10 times lower than that for good probes, i.e. around 30mOhm.

Trader:

--- Quote from: HKJ on March 19, 2021, 05:15:31 pm ---
--- Quote from: Trader on March 19, 2021, 04:52:41 pm ---A good (chinese) probe has resistance around 0.3 Ohm.

ProbeMaster around 0.25 Ohm

--- End quote ---

I would expect about 10 times lower than that for good probes, i.e. around 30mOhm.

--- End quote ---

Yes, my mistake, the correct tested values:


--- Quote ---I have 2 pairs from 2 sellers, they are very sharp (good), but they oxide easily and the resistance is ~100 mOhm.

A good (chinese) probe has resistance around 30 mOhm.

ProbeMaster around 25 mOhm

--- End quote ---

rsjsouza:

--- Quote from: free_electron on March 08, 2021, 03:49:09 am ---
--- Quote from: Monkeh on March 08, 2021, 03:14:28 am ---
--- Quote from: free_electron on March 08, 2021, 02:27:21 am ---- non standard plug arrangement. prevents me from using things like 0.75 inch pitch bnc to banana adapters, thermocouple interfaces and so many other banana plugs on 0.75 pitch

--- End quote ---
I'm pretty certain they are 0.75". All my 'weirdo' ones are, despite not being in a neat line.

--- End quote ---

but i want them in line... many pomona boxes and other 'adapters' bank on the 4 terminals to be either in line or in 'quad' (calibrators for example have ready wired blocks you simply plug in) . The key ones are the pitch between ground and Volt-ohm and ground-200mA range.  for low current measurements you may want to use coax or triax cables and then you need a bnc or to banana adapter. in the old version at least the mA/uA range is next to COM , in the new version it is too far away. the 10A range sits next to COM .. FAIL !

--- End quote ---

As Monkeh had said, all the meters I have/had that feature the triangular arrangement are also appropriately spaced to use the banana adapters in both current ranges - something impossible with the inline arrangement. But I also like the inline arrangement in larger meters. YMMV.


--- Quote from: free_electron on March 08, 2021, 03:49:09 am ---But the big stinker is the aspect ratio of the numbers. They are too hard to read. Fluke has the ideal ratio becasue they copied it from HP's 7 segment displays. ( fluke is actually a smidgen wider than a HP 7 segment. Also the way the segments flow into one another ( the chamfered edges ) makes a big difference in readability. The numbers need to be designed just right when it comes to width , height  , pitch and segment shape / angle. Fluke nailed it. So did HP. This elongated crap ? unreadable.

--- End quote ---
free_electron, I suspect you would be surprised how similar the displays of various meters are these days. Check my page at:
https://sites.google.com/view/vbeletronico/display-de-mult%C3%ADmetros

joeqsmith:

--- Quote from: SeanB on March 01, 2021, 06:15:13 am ---Nice meter, though 20A DC measurement, with a 10A fuse...... Guess it is the same current shunt, just with the "30 seconds maximum" there to prevent you blowing the fuse too often.

Waiting for Joe to blow it up, and if it will survive the grill starter lowest energy test that he has. My bets are it might just barely pass, but will fail on the higher energy tests. But at least they spent the 30c and added in the 3 MOV's to it.
...

--- End quote ---

I was recently asked about this meter and was told they had copied many of my changes to the 61E.  Doing a quick search, I didn't come across a schematic for it.     

The 61E would fail the first round of tests, pretty much like most UNI-T products I've looked at.  I gave up some of the frequency response to improve it's ability to handle an ESD event.  The PTCs were replaced and MOVs were added to handle the slower waveforms.   
The 61E had some of the worse burden voltages I have seen.   I had added a gain stage to improve one of the ranges. 
It had the worse temperature drift, second to my CEM meter.   I used a diode and resistor to compensate the reference.  It's now one of my more stable meters.
They had placeholders for the larger fuses which I took advantage of.  I then designed and constructed a new shunt for it.  Some of the PCB had to be beefed up.   

This meter would take some abuse now as I have shown in my testing.   

jspencerg:
This upgrade is obviously not perfect,  but meter has some good qualities.  Mr. Smith is the acknowledged expert about the 61e considering his extensive testing and improvements.  Joe, I realize your interests are elsewhere these days,  but could you give the 61e+ a look and assess the functional changes? I feel I've learned something by watching you modify the 61e.

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