How do we determine the turn-on voltage from a given I-V graph? 2. I have attached the picture. The graph which i need to obtain the turn-on voltage from is on the right. 3. I have searched the web and the closest answer I can find is from this website (link can't be posted due to lack of post) It says that "One method to consider begins with plotting the I–V data on a semi-log graph. Your data should approximate a straight line, indicative of the exponential nature of the current voltage relationship. An operational deﬁnition of the threshold voltage could be that value of the bias voltage when the current reaches 0.01 mA. Extrapolate your I–V curves to where they cross 0.01 mA current and use that as the working value of V0." However, during the briefing prior to doing the experiment and obtaining my data, the professor told find a gradient at one point of the curve and find the point where it intercept the x-axis (the voltage) which will give me the turn on voltage. No semi-log graph is needed here. But which point from the graph do i find the get the gradient to extrapolate? Thank you!!!!