Forward Biased Diode: Potential Rise vs Battery

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    Diode Semiconductor
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Discussion Overview

The discussion revolves around the behavior of a forward-biased diode compared to a battery, particularly focusing on the potential rise in the diode and the implications of current direction. Participants explore the characteristics of diodes and batteries, questioning the underlying principles and representations in diagrams.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants question why a diode connected with the P junction at a higher voltage and the N junction at a lower voltage results in a potential rise, contrasting it with the behavior of a battery.
  • There is a suggestion that a diagram could clarify the situation, indicating that the current direction and potential differences may be misunderstood.
  • One participant points out that a diode does not generate electromotive force (emf) like a battery does, which is a source of power with associated losses.
  • Concerns are raised about the accuracy of current direction in the diagrams presented, with claims that the current direction shown for forward bias may be incorrect.
  • Some participants express confusion regarding the representation of electron flow versus conventional current direction, suggesting that clarity in these representations is necessary for understanding.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the fundamental differences between diodes and batteries, nor on the accuracy of the diagrams presented. Multiple competing views and uncertainties remain regarding the interpretation of current direction and potential differences.

Contextual Notes

There are unresolved questions about the assumptions underlying the diagrams and the definitions of terms used, particularly regarding current direction and the nature of power sources.

Hydrous Caperilla
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If a diode is connected with P junction with higher voltage and N with low voltage then why is there a potential rise as opposed to the decrease in potential like in battery?
 

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Hydrous Caperilla said:
If a diode is connected with P junction with higher voltage and N with low voltage then why is there a potential rise as opposed to the decrease in potential like in battery?
Perhaps you should draw a diagram of this. It doesn't make sense, the way you have stated it.
 
I'm still not sure what you are asking but the characteristic curve https://www.electronics-tutorials.ws/diode/diode_3.htmlshows how an externally applied PD across a diode will affect the current through it.
Your two diagrams are showing two different applied PDs. Are you asking about the fundamental difference between a diode and a battery?
A diode is not a source of Power so there is no emf generated in it. A battery, otoh, is a power source and there is an emf generated along with some losses which can often be described in terms of an internal resistance.
 
Hydrous Caperilla said:
@sophiecentaur edited
The direction of the current shown in your case (b) of forward bias is backwards. The current flows from p to n when forward biased. You can see this from the Diode Equation:

https://en.wikipedia.org/wiki/Shockley_diode_equation

http://www.nptel.ac.in/courses/117107095/lecturers/lecture_2/images/fig1.jpg
fig1.jpg
 

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berkeman said:
The direction of the current shown in your case (b) of forward bias is backwards.
But it looks to me that the battery is connected the same way in both cases. The only difference is the battery volts. But his arrows seem to be showing the direction of electron flow, which is not helping.
I think it really would be better if he started again with a good source about diodes. He just seems a bit muddled.
 
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sophiecentaur said:
his arrows seem to be showing the direction of electron flow, which is not helping.
Oh, that's confusing. He should show current direction, IMO.
 

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