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AN8008 US $19, 9999count, 1uV, 0.01uA, 0.01Ohm, 1pF resolution meter

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floobydust:
The DTM0660 datasheet gives two schematics for a 3V multimeter; 13.1 QFP and 13.2 with die pinout. The pin numbers are much different, some pins are joined 2-1, at the corners or power pins.

HY12P65 has simple true-RMS DSP built-in as in the block diagram; the MCU at 4MHz cannot do much math on its own, and only 6KB code space.

AN8008 true RMS is rumored to not work with a DC bias on a sine-wave. I have not checked this.

tronde:

--- Quote from: floobydust on July 26, 2017, 04:26:34 am ---The DTM0660 datasheet gives two schematics for a 3V multimeter; 13.1 QFP and 13.2 with die pinout. The pin numbers are much different, some pins are joined 2-1, at the corners or power pins.

--- End quote ---

They don't differ that much. The numbers are different, yes, but they follow the same sequence on both. The die has three more pads, but three pins on the 64-pin is connected to two pads each on the die. Else they look similar.

evava:
Now, I have got the meter.

Continuity slower than I expected, uV resolution has unneeded gap around zero (shows only 0 or -5uV or +5uV  - nothing between), toy like.
No competitor to UT61e IMHO.

Price corresponds fully to usefulness.

Not very happy, wasted money for me.

Thank you all who have been trying in direction data logging, I read your contributions like detective story  ;)

ocw:
I changed my replacement for the AN8008 0.01 ohm current shunt resistor to a better option.  I put an IRC OAR1R100FLF 0.1 ohm resistor in its place and added a KOA SR733ATTE2R10F 2.1 ohm resistor it parallel with it.  The metric 6332 size of the resistor fits nicely with the existing trace after a bit of trace mask is removed.  Using the meter's AmA jack with the meter's switch in the uA position MY meter now reads XXX.X and XX.XX mA readings better than 0.1% accuracy.  Slightly less accuracy is available due to the resolution limit for X.XX mA readings.  Using the meter that way has the decimal point is in the correct position with a maximum current reading of 999.9 mA.

Due to the 1% resistors involved, other meters might require that a 2.2 or 2.0 ohm resistor be used in place of the mentioned 2.1 ohm resistor to achieve similar accuracy on your meter.  The approximately 5% change in resistor value will only change the parallel resistance by about 0.23%.  So, an even greater change in the value of the 2.1 ohm resistor might be needed.

Fungus:

--- Quote from: ocw on July 28, 2017, 05:33:06 pm ---MY meter now reads XXX.X and XX.XX mA readings with less than 0.1% accuracy.

--- End quote ---

Less than 1% accuracy? You mean more than 1% error?


--- Quote from: ocw on July 28, 2017, 05:33:06 pm ---Due to the 1% resistors involved, other meters might require that a 2.2 or 2.0 ohm resistor be used in place of the mentioned 2.1 ohm resistor to achieve similar accuracy on your meter.  The approximately 5% change in resistor value will only change the parallel resistance by about 0.23%.  So, an even greater change in the value of the 2.1 ohm resistor might be needed.

--- End quote ---

How about usiing a 2 Ohm, 25 turn trimmer? That should do the trick.  :popcorn:

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