Products > Test Equipment
AN8008 US $19, 9999count, 1uV, 0.01uA, 0.01Ohm, 1pF resolution meter
floobydust:
The 0.01R shunt takeoffs include the (high-current) copper trace on the PCB :rant:
So I would expect drift at high currents are the trace heats up, as it is part of the shunt resistance.
Next time they could try for pseudo 4-wire on that...
ocw:
--- Quote ---Less than 1% accuracy? You mean more than 1% error?
--- End quote ---
Sorry, my mind was locked into the per cent figure being lower which is obviously greater accuracy. I have corrected that to:
"better than 0.1% accuracy."
And, yes I mean better than 0.1% accuracy using a hand selected 1% resistor to provide the best accuracy. I don't think that this model meter warrants any effort for better accuracy than that.
Fungus:
--- Quote from: ocw on July 28, 2017, 08:31:46 pm ---And, yes I mean better than 0.1% accuracy using a hand selected 1% resistor to provide the best accuracy. I don't think that this model meter warrants any effort for better accuracy than that.
--- End quote ---
My comment was a bit of a joke, those 2 Ohm trimmers cost as much as the meter.
evava:
I wonder if that 8uV gap around zero (meter doesnt show values +-1uV +-2uV +-3uV +-4uV, instead of it only shows 0 or +-5uV or more) could be eliminated or at least reduced?
Is that set in EEPROM, or is it invariably written in firmware?
Is it possible to find out?
Otherwise it seems to be stable enough, I see no need to hide these small values (+-1uV +-2uV +-3uV +-4uV).
Kalvin:
--- Quote from: evava on July 27, 2017, 04:30:47 pm ---uV resolution has unneeded gap around zero (shows only 0 or -5uV or +5uV - nothing between), toy like.
--- End quote ---
I have two of these meters and the other one shows some intermittent fluctuating 5 uV - 10 uV offset voltage in DC mV range when the probes are short-circuited at room temperature. Now that I test this, the offset voltage displays 0uV, 5uV, 6uV, 7uV and 8uV, but no values between 1uV - 4uV. I guess there is some numerical hack so that the display is rounded down to 0 if the measurement value is below 5uV in order to hide this tiny offset voltage and avoid customer complaints. I can live with this, but it is good thing to keep in mind when measuring these tiny voltages.
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