Transfer Characteristics of Real and Ideal Diodes (and more sources)

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Discussion Overview

The discussion focuses on the transfer characteristics of real and ideal diodes, including their applications and related concepts in electronic engineering. Participants seek information on diode modeling, voltage ripple in rectifiers, and mathematical principles associated with digital electronics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant expresses difficulty finding resources that explain the transfer characteristics of real and ideal diodes.
  • Another participant describes ideal diodes as having no reverse breakdown, no reverse leakage current, and a right-angle break at the forward voltage.
  • It is suggested that ideal diodes would not have any forward voltage drop, implying full conduction at any forward voltage.
  • A participant requests assistance with the equation for voltage ripple in a half-wave rectifier, noting they have the full-wave rectifier equation but not the half-wave one.
  • Ripple voltage is mentioned, with a link provided to a Wikipedia page discussing time domain ripple.
  • Another participant presents equations for half-wave and full-wave ripple, expressing uncertainty about the peak voltage in the context of these equations.
  • A participant shares a calculation example for capacitance needed for a specific ripple percentage in a half-wave rectifier, questioning the correctness of their approach.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the specifics of diode characteristics or the calculations related to ripple voltage, indicating multiple competing views and unresolved questions.

Contextual Notes

There are uncertainties regarding the definitions of terms such as peak voltage and the assumptions made in the calculations for ripple voltage.

eximius
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I'm looking for information regarding the "Transfer Characteristics of Real and Ideal Diodes". I've tried google and the section on this site for learning material, but I've failed to find a site that displays both transfer characteristics and explains them. I was hoping that someone would have a site that discussed both or supply me with the information.

I'm also looking for a general site that would help me with UK university level electronic engineering work. Things such as diode applications, transfer characteristics, diode modelling, amplifiers and the maths associated with digital electronics such as boolean expressions, logic gates, truth tables and Karnaugh maps.

Any and all help would be greatly appreciated. Thanks.
 
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eximius said:
I'm looking for information regarding the "Transfer Characteristics of Real and Ideal Diodes". I've tried google and the section on this site for learning material, but I've failed to find a site that displays both transfer characteristics and explains them. I was hoping that someone would have a site that discussed both or supply me with the information.

I'm also looking for a general site that would help me with UK university level electronic engineering work. Things such as diode applications, transfer characteristics, diode modelling, amplifiers and the maths associated with digital electronics such as boolean expressions, logic gates, truth tables and Karnaugh maps.

Any and all help would be greatly appreciated. Thanks.

Welcome to the PF.

Wikipedia's intro to diodes is pretty good:

http://en.wikipedia.org/wiki/Diode

For ideal diodes, they would not have any reverse breakdown, and no reverse leakage current Is. They would also have a right-angle break at the forward voltage Vf, going from no conduction to full conduction (zero resistance).
 
Ideally, they wouldn't even have a forward voltage drop.

Any forward voltage on them would produce full conduction.

[PLAIN]http://dl.dropbox.com/u/4222062/real%20vs%20ideal%20diode.PNG
 
Last edited by a moderator:
Thanks guys. Massive help :)

Rather than starting a new thread. Could someone help me with the equation for the voltage ripple in a half wave rectifier? I have the full wave rectifier equation. But I can't find the half wave one anywhere on the internet. People only seem to be interested in the ripple factor.

Thanks again.
 
Ripple voltage is covered in this link:

http://en.wikipedia.org/wiki/Ripple_(electrical )

Click on it, then see under "time domain ripple".

Note that C is in Farads.
 
Last edited by a moderator:
So half-wave ripple = T/RlC

as r = dVl/Vm
and dVl = TVm/RlC

And full-wave ripple = T/2RlC

But I'm still uncertain about the Vm. Is it simply the peak voltage? As in points 1 on the sine wave?
 
I've got an example that seems to work with r = T/RlC

With a half-wave rectifier, calculate the capacitance needed for a ripple of 10% given an applied signal frequency of 50Hz and a load resistance of 500ohms.

r = T/RlC r = 10% = 0.01, Rl = 500ohms, T=1/f=1/50

.:.

0.01 = (1/50)/(500*C)
5*C = 1/50
C = 1/250 F
C = 4x10-3 F
C = 4mF

Am I correct in thinking this?
 
Bump, sorry.
 

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