Hi all, just wanted to ask a couple basic questions as I’m trying to get my head wrapped around this.
I’m trying to build a simple energy monitor for my sump pumps. I have a Particle Photon device and a 333mV 100A CT. I followed the documentation and setup something really simple with a 10k voltage divider and I had a 100uF capacitor laying around so I used that (I actually have two which I will put in in series to halve that). The Photon device provides 3.3V.
I understand the basic idea of what we are doing by adding the DC bias to the reading. What I’m struggling with is that even when the CT is not in a circuit I’m still reporting quite a bit of current. I followed some basic code and am using the current function since all I have is current.
What could I be missing that causes the program to report current when there is none?
The second question is about that calibration value. How is that calculated? I read something about the current which would produce a 1V output from the CT? My CT maxes out at 333mV so something doesn’t make sense in all of that.
Any kind of input would be greatly appreciated here, thank you.