DMM UNI-T UT210E

DSC_1320

This is a cheap clamp meter with DMM function.

DSC_1317

It included the DMM, a pair of probes, a pouch and a manual (Both a English and a Chinese version).

DSC_1337
DSC_1338

The probes has removable tip covers.

DSC_1339

The probes are rated for 10A, but it is not important for a clamp meter.

DSC_2841

The plug is fully shrouded.

DSC_1341
DSC_1322
DSC_1323
DSC_1324

DSC_1321 DSC_1325



Display

DSC_1332

The above picture shows all the segments on the display.
The circle with the arrow indicates auto power off, holding down the SELECT button during power on will disable that.

DSC_1333

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

DSC_1334

When using the NCV function the display will show a number of -, depending on the electric field. This can usual be used to see if a mains outlet or cable is powered or trace a cable that is just under the wall. This function is always a guideline and not a 100% confirmation of voltage or no voltage.



Functions

DSC_1336

Buttons:
Rotary switch:

Input

DSC_1419 DSC_1330

The two socket is used for V, Resistance, continuity, diode and capacitance

DSC_1328 DSC_1329

The clamp is used for all current measurements and for NCV. There is a red led at the bottom of the clamp to show when voltage is detected with the NCV function (Buzzer will also sound).



Measurements
1uF

A look at the capacity measurement waveform.

DMMschema




Tear down

DSC_1342

I had to remove two screws to open the meter.

DSC_1343

The circuit board is carefully made to fit inside the meter and use all aviable space.

DSC_1344

I assume the green wire is the NCV sensor

DSC_1345

The circuit board has some input protection with two PTC's and 3 MOV's. The input resistors (R37A, R37B, R37C, R37D: 4x2.5Mohm) is split into 4 resistors, between these resistors and the input is a PTC.
Close to the MOV's is a EEPROM (IC2: 24C02A) for parameter storage and some calibration, there is also trimpots for calibration.
There is a voltage clamp made with two transistors (Q4, Q9), it is not directly connected to input or output resistors but is probably switched in depending on range.
The big IC (DM1106EN) is the main multimeter chip and the frontend for the clamp is mounted close to it (U4:OPA4330 Quad OpAmp).


DSC_1346

One this side is another string of resistors (R27A, R27B, R27C: 3x300kohm), but strange enough they are connected directly to the input terminal without any protection. The NCV voltage led (LED3) and the transistor to drive it (Q2) is also placed here.

DSC_1416

There is also space for unused protection (Q6 & Q8). The backlight led is a side emitting led (LED2) mounted at the border of the LCD display.

DSC_1347

DSC_1348

The pink zebra stripe that connects the display to the circuit board can be seen here.

DSC_1349

DSC_1417
DSC_1418

Some backlight on the circuit board makes it easier to see the traces.



Conclusion

This meter is nice for measuring 100's of mA or more without any voltage drop, using it for lower DC currents requires careful use of the zero button.
It has basic DMM functions, but it missing frequency and low currents.
It looks like it has real input protection and the CAT rating may be correct.



Notes

How do I review a DMM