Analog Discovery 2 is affected by the notebook that we use

[latot]

Hi, I'm having some troubles getting a good measure, particularly, touch my notebook change the reading of the Analog Discovery 2 D:

Here an image, in the left the reading without touch the notebook, in the righ when touching.

 

This was particularly weird, first, to get this type of measure, the most sensible way, is just plug a cable in the positive of the first channel and keep there, without plug to anything else (can be done connecting to negative with a little more of work). The 50Hz, seems to be the electricity in my house, just connect a AC extension closer to the measure cable, every 50Hz and proportions will raise.

Now..., if I touch the usb cable, there is not much effect, just a little, but if I touch the notebook, specially the touch pad...., happens what you see up.

Have my hand closer to the notebook have readings too, touch a key too D:

I put the Analog Discovery 2 as far away as possible, but is the same....

My notebook is metalic.

Thx!

Edited May 11, 2022 by latot

[attila]

Hi @latot

You are seeing this behavior because your laptop supply does not have ground connection.

[latot]

D: The supply have ground connection, and is working, I test it with a socket tester.

[attila]

To verify the supply earth-ground connection, disconnect this from the socket and computer, use a multimeter to measure continuity or resistance between the earth contact and ground output.

[latot]

awww, there is no contact or resistance, like is not connected u.u

Put a ground connector in the note and my hand helps to reduce the interference.

Edited May 15, 2022 by latot