Hello,
I made a wiring interface for the DC power going into the board so that I can measure both Voltage and Current simultaneously. It looks like the attached .jpg pictures. The power brick goes to one end of the interface. The other end goes into the board. I am using that interface with a voltage divider and measuring voltage, current and plotting power graph using compact data acquisition device from national instruments (NI cDAQ - 9174). As seen in the video I attached to this post the voltage signals swings from 2.8 V to 4.9 V. I think, it should be smooth (with slight variations of course). You can see the smoothness at 21 seconds on the Video. That smoothness came when I attach the HDMI display cable to the board. Otherwise, the board does not have any peripherals attached to it.
Why do you think that the voltage is not smooth initially and why it becomes smooth after I attach the HDMI cable? Is it related to grounding? In that case how should I proceed with my measurements.
I can confirm that without the voltage divider, the signal is smooth. But, I need a way to somehow divide the voltage because NI 9215 I assume cannot measure above 10 V.
https://www.amazon.com/clouddrive/share/pwadVazQ1CpwAqwYGftgDfZ1Nme9ZpRjFD3wDuw17C?ref_=cd_ph_share_...
Thank you very much for your time.
