how to solve circuits that consist of diode?

Question

anonymous · Answer

You can use node method. V-I equation for diode is: $$ i_{diode}=I_0(e^{v_{diode}/vt}−1) $$

anonymous · Answer

Where $$I_0$$ and $$vt$$ are constants that value depend on what diode you are using. You can use values:
$$I_0=8*10^{-14}$$
$$vt = 0.026$$

anonymous · Answer

just consider that it will give you 0.7 Volt voltage drop. This works for most cases. But it should be hard to explain the whole reason in one answer. If you really want to know why, I can look for a good link and send it. BTW it is 0.7 volte voltage drop if the voltage is across diode follows the arrow. arrow should point to negative pole. It also called forward bias. If the polarity is reverse then the diode act as open circuit. You have to make sure that the reverse voltage is not more than zener potential, in most cases if you have just started studying about diodes, you do not care about zener potential.
I tried my best to teach all I read in my text book, I am studying a course about diodes this semester.

anonymous · Answer

@alireza.safdari can you give me some more information about diode.?i get confuss when i want to solve circuits that consist of diode?

anonymous · Answer

@TeWu thanks alot

anonymous · Answer

I am watching horror movie, I will reply back after the movie. Cheers.

anonymous · Answer

no problem. thanks alot.i hope to enjoy it (movie).;)

anonymous · Answer

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so now we have forward bias, which means that the diode will act as 0.7V drop voltage.
So, we have 5 - 0.7 = 4.3 V and then we know from ohm law that 
R=V/I => I=V/R
therefore 4.3/2 = 2.15 A
keep in mind that voltage drop will be 0.7 if the diode is made of silicon
if you need very accurate answer, you have to consider that each diode has a resistant so you have to replace it by one voltage drop and one resistance. Usually you cam ignore the resistance if it is much less than other resistance that you have in circuit. Resistance is dependent to diode.
All the above applies for when the diode is forward bias.
Here is 4:20 AM so if there is a spelling or grammatical mistake, don't be a grammar Nazi.