Calculation about dioide with ideal diode model method

[adrian116]

Homework Statement

This problem is to find the I and V by ideal diode model method (assume there is no voltage drop and resistance within the diode)

Homework Equations

Just simple Ohm's Law equation

The Attempt at a Solution

First i assume the diode 2 is open, but i don't know how to calculate the equivalent resistance of the circuit? is that just all in series or R4+R2//R3+R1?

 

[DefaultName]

I'm not sure what the V is referring to - remember the voltage is the difference in electric potential between TWO points, over an element.

Nodal analysis might be a good start.

 

[pooface]

If the diode is ideal i.e. has no voltage drop across it then the diodes are effectively shorts if they are forward biased. Based on this information, redraw the circuit and work from there.

 

[DefaultName]

The graph of an ideal diode looks like this:

http://physics.usask.ca/~angie/ep311/images/ideal_diode0001.jpg

which further reinforces what pooface said.

 

[little ing.]

new problem

The problem is:
Find I current and potential V for this circuit!