That’s a Seeed Studio module. It’s complete crap. They don’t bias the sensor’s output properly, so it can actually go below 0V (which is really bad for the ADC on the microcontroller).
If you look at the source code, all that GetCurrentReading() does is sample the current instantaneously (which, for AC, is useless). They have a method in there named “GetCurrentPeak()” – that’s probably the function you’ll want to use instead. It samples the voltage 200 times and spits out the maximum value.
Also, a stupid question: I don’t know the wiring color codes your cable is using, but are you sure you’re not clamped around the ground cable? if so, you’ll see little (if any) current.
I would engage you to use an ampermeter instead of a wattmeter as It can be confused between the active and reactive consumption which can be slightly different due to the dephasing of the signal, and the square(2) ratio that deals with MAX/RMS…and so on…
I have just measured the AC with a multimeter : 0.163A - 0.171A
But now I’m sure it’s the analog1 port of the cerbuino bee that doesn’t work. I tried with the analog5 pin and the CT sensor only ( without the gadgeteer module) and it returns me a value between 0.16A to 0.21A.
Now , I think my problem is my math, I attached you my code (is just a translation from the arduino code to c#) :