DMM UNI-T UT33A+

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This is a fairly simple and small DMM, but has a nice selection of ranges.

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The box is for all the UT33 meters with a checkmark for the actual model and a table on the back for comparing the models (in Chinese).
If you want all the function, you must buy all the models, none of them can everything.

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In the box was the meter, probe leads and a instruction sheet in both Chinese and English. The instruction sheet is for all four models in the series (A, B, C, D).

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The standard probes are about normal size, but rating them for 10A is on the optimistic side.

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The plugs are fully shrouded.

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With the meter lying flat it is possible to turn the switch, but on the tilting bale it will slide around.

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Display

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All the segments are shown during power on, not all are used by this meter.

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Typical display during usage, it will show the number and selected measurement



Functions

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Buttons: Rotary switch:

Input

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Measurements
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The meter is a true-rms meter.




Tear down

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I had to remove two screws, the battery cover could stay on.

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The circuit board is shaped to fit the box and uses ceramic fuses.

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I had to remove 3 screws around the range switch to get the circuit board out.

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And four screws to remove the lcd display, the backlight is soldered to the circuit board.

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There is no parts on this side, only pads for switches and lcd display and a marking of where ranges.

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The resistor for the uA range (R7: 99ohm) and uA range (R8: 0.99ohm) is protected by two diodes (D1 & D2: M7). The main input shunt is two resistors (R1 & R2: 2x5Mohm), there is also a secondary input chain (R4 & R5: 2X499kOhm). Ohm output is protected by a PTC (PTC1) and two transistors (Q1 & Q2).
The multimeter IC is a COP (Chip on board) that is bonded directly to the circuit board and then covered with some black stuff.

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Conclusion

The CAT rating do not match the fuses used, i.e. it is not correct, but at least it use fuses and fairly good ones.
The meter has a nice selection of ranges, but is missing frequency and min/max functions for a general purpose meter. This is the best meter in the UT33+ range, but the other meters in the range each has one function this meter is missing (Battery test, temperature, NCV).
I was a bit surprised that this meter is a true rms meter.



Notes

UNI-T do often make rebranded meters, i.e. it may exist with other names on it.

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