Clipping circuit

Tested a clipping circuit to protect the Arduino input pins from overvoltages. The Arduino Due pins cannot handle voltages above 3.6V or below -0.3V. ADC values are clipped at 3.3V and 0V. The Zener diode used is the 1N5227, and has a Zener voltage of 3.6V.

This resulted in the following waveforms, yellow being input to the clipping circuit and green being the output the Arduino would read.

These 10000 datapoints were used to create an equation to map the Arduino read voltages to the actual unclipped values:

y = 0.0872x3 - 0.2738x2 + 1.2169x

This trendline has an R^2 of 0.9993