new to this so please be kind.
want to measure AC current in domestic supplies using an atmel ATMEGA328P chip wit the best resolution possible
I need to use the split core current transformer sensors I have which output 0.333vac for the sensed current they are rated to - http://www.magnelab.com/wp-content/uploads/2015/03/AC-Split-Core-Current-Sensor-SCT-0400_specsheet.pdf
I have a regulated 3.3v supply which runs the chip and the internal analogue reference is 1.1v.
I have tried creating a potential divider using the 3.3v supply and 100k and 560k resistors to give 0.5v and then connecting the ground of the CT to the 0.5v point and the output of the CT to the ADC (with 1.1v analogue reference).
My problems are
- the resistors seem to have stopped working (am i using bad values?)
- the samples are inconsistent, at the moment i am taking 100 consecutive samples using a for loop in the AVR code and then calculating RMS voltage by subtracting the 0.5v bias and doing standard rms calculation... should i be sampling at a particular frequency and if so does anyone know how i go about controlling this on the chip I'm using.