Mini Lab : measuring current


I tried to measure current with my mini lab.
I follow the example in the documentation ( connect shunt input to 0.5v input, connect a restistor between 5v and shunt), it does not work.
When i connect the shunt input with 0.5v input, it seems, it blocks the mAmp display to the previously displayed value. When I remove the shunt-0.5v, the 3rd display is always changing when mAmp is selected.

Do I miss something ? What goes wrong ?

(Totem minilab v2.2)

Hi, welcome to the forum!
The current measurement feature reuses 0.5V input for the measurement (just recalculates the flowing current value from the Ohm’s law). As the shunt is ~0.47 Ohm, the resulting current value should be roughly double what the 0.5V input “sees”.
If you haven’t connected 0.5V input to the shunt input, you should expect to see measured values to float around a bit, but it should go down to zero when connected.
We also have a calibration routine available that can self-check and correct measured and actual values. It’s described in section 8 here:
Maybe you could attempt to do the calibration routine, and see if that helps?


I tested the calibration routine, and since, all is right !
I tested multiple resistors, and get the expected values.

Thanks for your help, and great thanks to all the team for the mini lab concept. All in one and easy to use test platform to play around Arduino & electronic !

A lot of fun to come :slight_smile:

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I just started to use the TotemMaker minilab. When testing the current measurement function, I found out that the mA display shows 50 mA with a test resistor of 100 Ohm, instead of 5 mA as what the user guide shows. Looking at the measuring circuit, I see that we power the circuit with 5V. According to Ohm law the current should be (5/100)*1000 = 50 mA. Is the user guide correct?