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Franck Hertz Graph

  1. Nov 27, 2013 #1

    How can I determine when the current is starting rise? What methods should I use to do so? on excel or matlab.

    I've attached an image of my graph below

    Thanks a million

    Attached Files:

  2. jcsd
  3. Nov 27, 2013 #2
    Er, can you use a ruler?
  4. Nov 27, 2013 #3
    that's what I did on my last lab, for planck's constant, but apparently I need some systematic way of determining it according to my TA
  5. Nov 27, 2013 #4
    I'm writing a formal lab report for Franck Hertz oscillation
  6. Nov 27, 2013 #5
    Can you plot the gradient using Excel. Then if possible say when the increase in the gradient becomes statistically significant?
  7. Nov 27, 2013 #6
    how do I find the gradient? (sorry I'm not really good at this)
  8. Nov 27, 2013 #7
    Or may get Excel to determine the best fit line. It will tell you the equation of the line and where is crosses the x axis.
  9. Nov 27, 2013 #8
    If you don't know how look up trend lines in Excel help.
  10. Nov 27, 2013 #9
    I tried fitting an exponential and linear line, but it didn't work. it was way too off. But why would the would I be looking for a y-intercept of the line? (where it crosses the origin)
  11. Nov 27, 2013 #10
    oops, i meant to say why would I be, not why would the would I ....haha
  12. Nov 27, 2013 #11
    Rather than plot the current, you could plot the change in the current. That would be the change in each current measurement divided by the each little change in your input variable. That would be the gradient.
  13. Nov 27, 2013 #12
    Sorry, I meant the x axis. And you can't use all the points - you need to exclude the flat part, else you will get rubbish.
  14. Nov 27, 2013 #13
    I think the gradient plot sounds good! thanks so much!
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