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Understanding exp Function in Ebers-Moll Equation & X>>Y's Meaning in Transistor Operations

Axel_cpu 38562 6
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  • #1 307088
    Axel_cpu
    Level 11  
    The Ebers-Moll equation is as follows:

    Ic=Is[exp(Ube/Ut)-1]

    Question - what does exp mean - I know it's some function, the problem is that I don't know what to do with it. Suppose I have calculated the ratio of Ube to Ut and I don't know what to do next with it.

    Second question - what does x>>y mean. For example, in the area of active operation of the transistor Ic>>Is.

    I can't find it anywhere on the internet, I hope someone can explain it to me in an easy to understand way.

    Regards,
    axel_cpu
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  • #2 307100
    elektryk
    Level 42  
    Axel_cpu wrote:

    Ic=Is[exp(Ube/Ut)-1]

    exp(x) is the exponential function e^x (e to the x power, where e is the constant math approx 2.7 )
    Axel_cpu wrote:

    Second question - what does x>>y mean. For example, in the area of active operation of the transistor Ic>>Is.
    that is, Ic is much, much larger than Ic (something like a double greater than sign) it is a conventional symbol.
    PS in which transistor do you have Ic and Is? any IGBTs?
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  • #3 307112
    Axel_cpu
    Level 11  
    Thanks for the answer. And what exactly is the mathematical constant e and where does it come from? Is and Ib of an ordinary bipolar transistor. In the book "The Art of Electronics" Is is the designation of the saturation current of the transistor.

    Regards,
    axel_cpu
  • #4 307124
    elektryk
    Level 42  
    Mathematical definition
    e= limit lim [(1+1/n)^n] for n -> infinity
    its value is, like the numbers pi, infinite, a more accurate value than I gave before (found on the web)
    e= 2.71828182845904.....

    by the way, the function e^x has an interesting property
    e^x= derivative d(e^x)/dx = integral (e^x) dx
    but that's a whole different story
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  • #5 307133
    Axel_cpu
    Level 11  
    Many thanks again. I'm learning electronics and the biggest problems for me are maths (I just finished middle school and I didn't have integrals and differentials). Lectures from college don't give me much because I don't understand most of them. Now I downloaded the material about complex numbers (electrode>aids>complex numbers) by Piotr Górecki. I hope to understand it. I like his way of translating, I haven't had any problems understanding his texts yet. If anyone knows where I can find "lectures" of mathematics written in the language of pathology (so that a junior high school student understands) then please let me know.
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  • #6 307218
    elpiko
    Level 17  
    Very pathologically:

    exp it's a button on a calculator.

    This is the inverse of logarithm.

    E.g.

    a*b = exp (log a + log b) because log a + log b = log a*b
    (I hope I'm not mistaken - holidays are here

    This is an example of analog multiplication
  • #7 307412
    elektryk
    Level 42  
    elpiko wrote:
    exp it's a button on a calculator.
    The EXP button on the calculator means (number)*10^(number)

    elpiko wrote:
    This is the inverse of logarithm.
    Only for natural logarithm.
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Topic summary

The discussion centers on the Ebers-Moll equation, specifically the meaning of the exp function and the notation x>>y in transistor operations. The exp function is identified as the exponential function e^x, where e is approximately 2.718. Users seek clarification on how to apply the ratio of Ube to Ut in calculations. Additionally, the notation x>>y indicates that the current Ic is significantly larger than the saturation current Is in active transistor operation. The mathematical constant e is defined, and its properties are briefly discussed. The conversation also touches on the challenges of understanding electronics and mathematics for beginners.
Summary generated by the language model.
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