Solving Diode Equation for Current?

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The discussion centers on solving the diode equation for current, highlighting the challenge of rearranging the equation due to the presence of current (I) in the exponential term. Numerical methods, specifically Newton's method, are suggested as a solution approach for finding I. There is also a query about the diode ideality constant, with users noting that it typically ranges from 1 to 1.5, but the absence of a specific value in the manufacturer's data sheet leads to uncertainty. It is mentioned that varying the ideality factor between 1 and 2 does not significantly affect the current in simulations, indicating it may be negligible for the modeling task. The conversation reflects the complexities of diode modeling in MATLAB and the reliance on numerical methods for accurate results.
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Homework Statement



I need to find the current, but not sure how to rearrange the equation because of the I in the exp.

Homework Equations



wmbeyd.png


The Attempt at a Solution



Thanks, just need to be pointed in the right direction. Seems like I will either be in ln or exp.
 
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Also, just a follow up question, the diode ideality constant... Is there a way to solve for it? My notes just say its between 1 - 1.5, Should I just assume its 1? The manufacturers data sheet does not mention a value for this.
 
physics_197 said:

Homework Statement



I need to find the current, but not sure how to rearrange the equation because of the I in the exp.

Homework Equations



wmbeyd.png


The Attempt at a Solution



Thanks, just need to be pointed in the right direction. Seems like I will either be in ln or exp.
Because I appears on its own and as the argment of the exponential, you can't solve for it using elementary operations.
 
physics_197 said:
Also, just a follow up question, the diode ideality constant... Is there a way to solve for it? My notes just say its between 1 - 1.5, Should I just assume its 1? The manufacturers data sheet does not mention a value for this.
Are you talking about I0? That one you can solve for.
 
No, I'm talking about just I. So how would I go about finding it?
 
physics_197 said:
No, I'm talking about just I. So how would I go about finding it?
Using numerical methods
 
Thank you, I used Newtons method on matlab, I think it should be correct :)

Also, do any of you have an idea about the diode ideality factor? I am trying to model a PV module in Matlab and the data sheet does not mention this. I read online that people tend to assume its just 1... Any ideas?
 
Nevermind! After running through the code using different values (between 1 and 2), There is no difference in terms of the current... well either, it can be neglected or my code is wrong (I tried entering a large number, that affected the current)
 
physics_197 said:
Thank you, I used Newtons method on matlab, I think it should be correct :)

Also, do any of you have an idea about the diode ideality factor? I am trying to model a PV module in Matlab and the data sheet does not mention this. I read online that people tend to assume its just 1... Any ideas?
Which variable is the diode ideality factor? That's what I was asking about in post #4.
 

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