Posts Tagged ‘UT71C’

UNI-T UT71C Accuracy Check

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I borrowed a DMMCheck Plus from my colleague today and decided to check the accuracy of my multimeters. First up is the UT71C multimeter from UNI-T. It’s a 40000 count TrueRMS meter with decent specifications. Let’s see if it passed with flying colours or failed miserably!

Here is the actual DMMCheck Plus with its specification sheet if anyone is interested:
DMMCheck Plus DMMCheck Plus

And now let’s take a look at the results. Both the DMMCheck and UT71C were left alone for around 30 minutes to get to know each other and for their references to stabilize (room temperature was 21C/70F). UT71C is around 4 years old, with factory calibration.

AC/DC voltage measurement: passed!
UT71C AC Voltage Measurement - 5V RMS UT71C DC Voltage Measurement - 5V

AC/DC current measurement: passed!
UT71C AC Current Measurement - 1mA RMS UT71C DC Current Measurement - 1mA

Frequency and duty cycle measurement: passed!
UT71C Frequency Measurement - 100Hz UT71C Duty Cycle Measurement - 50%

Resistance measurement: passed!
UT71C Resistance Measurement - 100R UT71C Resistance Measurement - 1k
UT71C Resistance Measurement - 10k UT71C Resistance Measurement - 100k

And there you have it, not bad at all considering the price! I do have to mention that the current measurement was fluctuating a bit with the backlight on (it’s probably a good idea to replace the battery).

UPDATE: I stand corrected on the previously “failed” AC current measurement. According to the manual (which I haven’t fully read), AC current accuracy is lower than what’s indicated on the UNI-T’s web site and only valid within 10-100% of the range. I tried to measure 1mA on a 40mA range and that is lower than the 10% of the range to meet the specified accuracy. Big thanks to Wytnucls at EEVBlog Forums for pointing this out!

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