UNI-T UT210E clamp meter, a user tip :) - Page 1
Forum section: electronics / beginners

author: Electro Fan
author_rank: Super Contributor
timestamp: January 20, 2018, 09:28:28 pm
content: Just sharing some learning.As a mostly self taught electronics enthusiast (an Electro Fan), I've been able to get my head around much of Ohm's Law and have gradually worked my way up from the bottom. Resistors weren't too difficult to figure out, impedance and reactance are still a works in progress, capacitors are getting there, transistors have a long way to go, but for some reason inductors have been a bit over the horizon. (I get that capacitance and inductance contribute to reactance, etc. but for some reason when things go magnetic instead of electric it causes extra head scratching.) Nonetheless, my favorite way to learn all this stuff has been just to measure values and see if I can make heads or tails out of the direction values go - up or down, and then do some math to see if things are fitting together. And then it's on to making some new circuits or finding some pre-made circuits, or read about something interesting to measure, and then measure some more. Descartes said "I think, therefore I am". In my case, I measure, therefore I am.Recently after reading the Test Equipment thread on the UNI-T UT210E clamp meter I decided it would be a good investment. I figured that having a clamp meter that measures DC in addition to AC might be useful. Sure enough, in the process of doing some tests to confirm that the 210E clamp will measure down to about 1 or 2 mA DC (there is some amount of error and uncertainty) I noticed that I was getting negative values when I expected positive values. I checked the cables from my power supply to the load - they were all attached to the proper terminals with conventional color coding. Next I tried a couple other DMMs and they confirmed that the current was flowing in the direction as expected. (To double check I reversed the DMMs and they showed negative values when I expected negative values.) Then I had a bit of an "A Ha" moment and realized that I had been running the two conductors (one at a time as you would expect with a clamp) in a way that made reading the 210E display easy, but in a way that was backward (with respect to the direction the cables were taking through the clamp). Sure enough, when I flipped the clamp around 180 degrees the values (positive and negative) made sense.What I think I learned is that to get the polarity correct the clamp needs to properly face the source (on the red/+ cable) and face the load (on the black/- cable). Slowly, very slowly, it's starting to sink in.PS, Thanks to Maxlor and everyone on this thread:https://www.eevblog.com/forum/testgear/a-look-at-the-uni-t-ut210e/PSS, Thanks also to Dave. When I got the meter it looked really good, felt solid, and operated well but I wanted to be sure it had the latest chip (DM1106EN). A few years ago I would have said "why goof around with a brand new piece of gear that is working well?" I know, no big deal opening the case but before contracting EEVblog-itis I would have gone the conservative route and left well enough alone. In this case I was still almost ready to forgo looking but then I heard Dave's words, opened it up, and sure enough it has the DM1106EN....edit for typos