Recent content by marc1uk

  1. M

    Why does light shift the pn junction IV curve right instead of steepening it?

    Thanks, I think I did come across that site, but the trouble is it'd be a whole lot of effort to explain a whole lot more than I need really - I couldn't go to that much detail in my essay, and I don't have the time right now (stupid idea having coursework during exam week anyway) to learn it...
  2. M

    Why does light shift the pn junction IV curve right instead of steepening it?

    H-H'mmm... Well, thanks for the reponses. Deadline was just now, in the end I really just had to make do & hope for the best, I'll ask one of the professors later, just as soon as i can track one down. Who knows, may have all been some experimental glitch.
  3. M

    Why does light shift the pn junction IV curve right instead of steepening it?

    H'mm... this is something I've overlooked, good point.
  4. M

    Why does light shift the pn junction IV curve right instead of steepening it?

    ... You increase.. what? By applying a forward bias potential to turn the diode "on", you physically increase the size of the depletion zone...? By annihilating more e/h pairs, maybe you would produce more ions in the depletion zone to increase the opposing voltage across it, but surely the...
  5. M

    Why does light shift the pn junction IV curve right instead of steepening it?

    :rolleyes:I fear this is getting a bit above my level. (I also don't quite see what a Zener diode has to do with it, just an example of diode-specific effects?) If it's a diode-type specific effect then hopefully I won't be marked down for not knowing why it happens.
  6. M

    Why does light shift the pn junction IV curve right instead of steepening it?

    The experiment was performed on eight different diodes, but based on what I've been told of pn junctions the effect should be the same, though of different magnitudes. The observations were actually made on a photodiode, since it was the only one which showed a large enough response to be...
  7. M

    What are the direction and magnitude of the net electric field

    Firstly, E1 = kq/r^2 gives you the magnitude of the electric field, not the force, so will be in N/C, not N. You'll also want to use the true value of q, not it's magnitude, since you need a direction as well. Assuming the point P is where you're measuring the field, and is at the locus of the...
  8. M

    Why does light shift the pn junction IV curve right instead of steepening it?

    [SOLVED] urgent: effect of light on IV characteristic of pn junctions ^ ^;; Last resort time, needs to be answered by 4pm today. (18/01/08) It's a pretty qualitative question, and if possible I'd like a qualitative answer. The reason for this is that this is only a weekly experiment I've...