@stereoplay
Thanks alot. Done the test again with a better ADC and got better results:
2nd harmonics is lowered to 0,20 %
2nd harmonic 0,20 %
3rd harmonic 0,048 %
4th harmonic 0,019 %
5th harmonic 0,0090 %
6th harmonic 0,0045 %
7th harmonic 0,0037 %
8th harmonic 0,0032 %
9th harmonic 0,0028...