1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Ohm law

  1. Jul 23, 2009 #1
    how do i go about answering this question guys, send me in the right direction please :)

    "when a diode allows a positive current to flow it has a resistance of 0.5kohms. It does not allow negative flow, i.e. the resistance is infinate. using ohms law, sketch a graph of current I against voltage V for both negative and positive values."

    i knw that ohms law states that the potential different is directly proportional to the current flowing throught the system providing the temperature remains constant, how do i find the values for I and V to use for my graph :)
  2. jcsd
  3. Jul 23, 2009 #2


    User Avatar

    Staff: Mentor

    What is the equation that relates V and I in terms of R? Plot that for the two separate regions, V>0 and V<0.
  4. Jul 23, 2009 #3


    User Avatar
    Gold Member

    I don't think that you need them but perhaps I'm misinterpreting the question. We know that if a positive current flows then R = 0.5 k(ohms), regardless of the voltage (if V > 0) or the current. Using what you know about the resistance and ohm's law V = IR you should be able to draw a suitable graph.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook