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| UNI-T UT61E Multimeter teardown photos. |
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| indman:
--- Quote from: Fungus on September 18, 2020, 07:23:40 am ---maybe you got a bad one. --- End quote --- No, I have the same UT61E as the majority of users. ;) If you look closely at the table with the results Mickle T., the link to which I indicated above, you will see that in his UT61E in the same experiment with 4 resistors, at the 22kΩ limit, the deviation from the theoretical value was 12Ω. The UT61E is a good instrument for its price category, but if I need to accurately measure some kind of resistance, I entrust this work to other instruments that have digital calibration on each measurement range. |
| Fungus:
--- Quote from: indman on September 18, 2020, 08:29:18 am ---If you look closely at the table with the results Mickle T., the link to which I indicated above, you will see that in his UT61E in the same experiment with 4 resistors, at the 22kΩ limit, the deviation from the theoretical value was 12Ω. --- End quote --- OK, but the whole "adding resistors together" is surely a red herring. The problem is more likely that you're at 22 kOhms on a 22000 count meter. Maybe the auto-ranging is freaking out internally. What happens if you lock the range manually? Even if it stays the same: You're still on the limits of the ADC and still easily inside the 0.5% spec of the meter. |
| myf:
Hello everybody, and excuse my poor English for these very interesting posts. a 22000 count meter is at full scale for a (little less) than 22Kohm resistor. Fungus do you explain that at this full scale, ADC have a more important relative error (in percent) ? Where is the best range ? With this ut61e I often measure 0 count for a very low 5 count (over 22000) real value. Can we model : "a more precise (or real) value" = "a fixed offset count" + "a rate around 1 as 0.995 or 1.005 " * the measured value ? Indman results are interesting, I got about same values with my tests. Can we detect what is the error of each measure ? Of course all these values are inside the assumed error rate for this multimeter. On the other hand an offset error = + 4 counts improve these set of measures. This is the opinion of the mathematician, not that of a physicist. In this case, the measurements are almost perfect at +/- 1 unit. What is your advice? I don't have neither precise resistors (but 10Kohm maybe at 0.01%) neither 5.5 or more digits multimeter. I have a set of 1% (or 5%) standard resistors. Suppose you establish a serial link with 20 resistors: each resistance = 100 ohms and 1% error. Then I measure AND each resistor, AND all of those partial links of 1, 2, 3, ... 20 resistors. So I can build the table of "X = sum of measured resistances" (= 98 + 101 + 99 for example) and "Y = measured value" (= 398 in this case). What information can I get from this graph? Of course, I don't know if the error is "inside each resistor" or "in the multimeter" ! What (other) simple and common tests are possible with one or two multimeters? F. from France. |
| rsjsouza:
--- Quote from: tecnicaemail on September 17, 2020, 06:22:36 pm --- --- Quote from: Mickle T. on September 17, 2020, 06:01:20 pm ---UT61E has one of the best resistance measurement linearity among mid-range handheld multimeters. These results was obtained by use of precision impedance synthesizer with a 2 ppm linearity error. --- End quote --- So between U532 and U61E, better to stick with 61? --- End quote --- tecnicaemail, I looked at the UT532 and it is an insulation meter as well as a multimeter without the A range. Considering this, the UT61E is a better general purpose multimeter, while the UT532 has a very specialized function. The choice depends on what you already have and what you do. If you have other multimeters and the UT61E is just one more, then the UT532 has a unique function that may be interesting to have in case you need it. Otherwise, I would choose the UT61E as it has more useful features. |
| Lenny:
I also have the UT61 multimeter. Unfortunately, the automatic range selection does not work when measuring resistance. All values are displayed in the megohm range. Even with small resistances, the device no longer switches into the small ohm or kilo-ohm range. If I turn the function selector with a resistor already connected, e.g. from volts to ohms, the correct range is displayed. Switched to the manual mode, I can only switch from Ohm -> kOhm -> MOhm, but not back. It stucks in MOhm Has somebody an idea? |
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