Questions tagged [ebers-moll]
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15
questions
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1answer
56 views
Do Ebers-Moll model cover all working modes of BJTs?
I mean the normal working modes (cutoff, forward/reverse active, saturation).
Or an other form of the question: Do Ebers-Moll cover the whole working domain of BJT (in potential and current values)?
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0answers
17 views
What is value of Reverse Saturation Current (Is) for BC547B NPN transistor
I am trying to evaluate Ebers Moll equation for estimating collector current for a given V_BE at DC conditions. The datasheet of BC547B (which I am using) does not mention the Is (i.e. Reverse ...
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14 views
Derive the expressions for the i-v characteristics of these configurations of NPN Transistors. Part (a)
I just need part (a) to be solved because then b would be trivial.
I am using the Ebers-Moll model equations but somehow my final solution doesn't have alpha_F and alpha_R and i know that shouldn't ...
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2answers
107 views
How to use Ebers-Moll equation to calculate collector current?
The Ebers-Moll equation is given by:$$I_C = I_S(T) * (e^{V_{BE}/V_T})$$
where \$V_T\$ = \$kT/q\$ = 25.3mV at room temperature. In TAOE (2.3.1), it mentioned
\$I_S(T)\$ is the saturation current of ...
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0answers
70 views
How to calculate Current Emitter (Ie) using Eber-Molls model on an NPN transistor
my computer science professor gave us a problem to code in python involving Ebers-Moll model for circuits where he asks us to find the current emitter (Ie). In the program we ask the user to give us ...
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1answer
118 views
Question on Ebers-Moll model
I have what should be a simple misunderstanding of a piece of text from "RF Circuit Design" by Lugwig. I am not in a class, just self-teaching. This book has been quite helpful, and I have not found ...
3
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1answer
146 views
What part of Ebers-Moll equation shows the decrease of the collector current in saturation region
By looking at the Ebers-Moll equation for a BJT transistor:
Is this formula explicitly showing why Ic starting to decrease towards zero in saturation region. Which part of the equation shows that?
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146 views
Reverse biased diode formula in Ebers-Moll model
As far as I understand in an PNP transistor the base voltage Vb is higher potential than the collector voltage. So since Vb>Vc the base collector junction is then reverse biased:
But in Ebers-Moll ...
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1answer
216 views
Operation of BJT with low values of Vbe (“cutoff” region)
Many sources claim that when the base-emitter voltage becomes smaller than approximately 0.6V-0.7V, the bipolar junction transistor goes in the cutoff region and there is zero base and collector ...
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1answer
1k views
Saturation current in Ebers-Moll equations for BJT: what is it and how to measure it?
In Ebers-Moll Equations for common emitter BJT the inverse saturation current \$I_s\$ appears as a parameter. What is the saturation current \$I_s\$ exactly and how should I measure in a common ...
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2answers
194 views
Ebers–Moll model aF? Where does it come from?
I am just getting back into electronics after a long while. For the life of me I can't figure where the \$\alpha_F\$ variable in the Ebers–Moll model comes from when you are calculating \$I_C\$ or \$...
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1answer
326 views
An NPN BJT - from Spice to Ebers-Moll
Wikipedia reports a simple model for a BJT in active mode (an approximation to the Ebers-Moll model):
\$I_E=-I_{ES}(e^{V_{BE}/V_T}-1)\$
(in the NPN case). Here, \$I_{ES}\$ is the Base-Emitter ...
1
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1answer
175 views
Which equation of the Ebers-Moll-Model is correct?
I'm confused.
In different sources sometimes I find the equation
\$ I_C = I_S\cdot\left(e^{\frac{U_{BE}}{U_T}}-1\right) \$
or like wikipedia
\$ I_C = I_S\cdot e^{\frac{U_{BE}}{U_T}} \$
Can ...
1
vote
1answer
202 views
Collector currents of different BJT Models and Ebers-Moll
Per Horowitz&Hill book, the Ebers-Moll equation for the collector current in a BJT is:
Ic = Is (e ^ (Vbe/Vt) - 1)
where Ic is the collector current and Is is the saturation current.
Now, I am ...
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5answers
981 views
Can you find an analytic expression for the (beta)hfe of a BJT?
I understand there are two models \$Ic=\beta Ib\$ and \$Ic=I_s exp (\frac{V_{BE}}{Vt})\$ for a bipolar junction transistor.
However (correct me if I am wrong), I have not seen any textbook ...
