Clippers in Diodes: Current Flow Explained

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Discussion Overview

The discussion revolves around the operation of diodes in clipper circuits, specifically focusing on current flow and the behavior of the diode with respect to positive and negative voltage pulses. Participants explore the implications of forward and reverse biasing in the context of voltage clipping.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether the graph associated with the diode's behavior should reflect the opposite current flow, suggesting that positive input should allow current to pass through the diode.
  • Another participant explains that the clipper removes positive pulses from the output voltage, indicating that the diode conducts during positive peaks and limits the output swing to 0.6V.
  • Several participants inquire about the reasons for the removal of positive pulses and the lack of clipping for negative pulses, with one noting that the diode does not conduct when reverse biased, thus not affecting negative excursions.
  • Another participant expresses confusion about the operation of the diode, suggesting that it should remove negative pulses instead, given that it is forward biased for positive input voltage.
  • One participant emphasizes that the diode conducts on positive peaks, preventing them from reaching the output.
  • A later post seeks clarification on the conditions under which the diode is forward biased, asking for a detailed explanation of the voltage conditions required for conduction.

Areas of Agreement / Disagreement

Participants exhibit disagreement regarding the behavior of the diode in clipping positive versus negative pulses, with no consensus reached on the correct interpretation of the diode's operation in this context.

Contextual Notes

Some assumptions about the definitions of forward and reverse biasing may not be explicitly stated, and the discussion does not resolve the mathematical or conceptual details surrounding the clipping behavior.

Who May Find This Useful

This discussion may be useful for students and practitioners interested in electronics, particularly those studying diode applications in circuits and the principles of voltage clipping.

M. next
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Observe the attached figure, and the associated graph, shouldn't be like the opposite of this graph?

If it is positive the first half the current should pass the diode and it is on, no?
 

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The output of the clipper is vo. The clipper removes the positive pulses from vo. The diode conducts on the positive peaks, limiting their swing at 0.6v
 
Why does it remove the positive pulses?
 
Why not the negative one?
 
M. next said:
Why not the negative one?
The diode doesn't conduct when it is reverse biased, so it is effectively not present for negative excursions of vo thus negative pulses are not clipped and they remain unaffected.

The input is on the left, the output is the voltage on the right. Maybe it would be clearer if the line marked "—" were to be labelled "ground". https://www.physicsforums.com/images/icons/icon6.gif
 
Last edited by a moderator:
Please elaborate more, I know that the diode doesn't conduct when it is reverse biased.
Here we have Vi as input voltage, and as you can see in the figure it should be forward biased for positive input voltage, and thus we should remove the negative pulse - not the opposite.
 
The diode conducts on the positive peaks so they don't make it to the output.
 
Hmm, probably my question is not very clear, right?
The diode allows the passage of voltage if it is in a way that goes along with the pointer head "arrow like" and this " | " or in other words if "Vp-Vn>0".
Let me post my question in a different way: here if voltage from input passes through the diode when it gives a positive pulse, will it be forward biased or not? And why? With details please.
 
And thanks for your time in advance
 

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