# Another diode problem from the Hayt/Neudeck 2nd Edition...

Discussion in 'Homework Help' started by grasshopper, Feb 20, 2014.

1. ### grasshopper Thread Starter Member

Apr 2, 2009
11
0
Two identical diodes, each having I_0 = 1 fA and n = 1.1, are connected in parallel. The combination is connected in series with 150 ohms and a 1.5 V battery so that the diodes are forward based. Calculate the source current at 25 Celsius if

a) each diode is represented by a piece-wise linear model that is exact at 0.5 and 5 mA;

b) each diode is modeled by the nonlinear diode equation.

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In reference to the text that i made bold, what exactly is meant by this statement? I'm assuming that the author meant I_D = 0.5 mA and I_D = 5 mA.

First off I want to make sure that I understand this problem correctly.

Can someone please confirm if I have the right idea here by taking look at the attached sketch? I have a feeling I don't, so I might need some help here.

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2. ### WBahn Moderator

Mar 31, 2012
18,087
4,917
I think this time your prior interpretation is correct. The description is for the entire circuit consisting of a battery, a resistor, and the two diodes.

And, yes, you are correct in that they are saying that the piecewise linear model is set up so that it matches the nonlinear model at Id = 0.5mA and at Id = 5mA.