# Homework Help: Ohm law

1. Jul 23, 2009

### JakePearson

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. Jul 23, 2009

### 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.

3. Jul 23, 2009

### jgens

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.

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