Comment by periblepsis on Is it mathematically possible to solve for base...
@nuggethead It's solvable by using branch-0 of the LambertW (product-log) function. There are a number of papers on the topic. But its in the scientific literature. Not in undergrad textbooks. If you...
View ArticleComment by periblepsis on How does a BJT maintain a constant collector...
Matteo: Seriously, "Physical Electronics and Circuit Models of Transistors" by Paul E. Gray (MIT), David DeWitt (IBM), A. R. Boothroyd (Queen's Uni of Belfast), James F. Gibbons (Stanford), 1964, vol....
View ArticleComment by periblepsis on Thevenin theorem conditions and inquiries?
I'm reading your writing and finding only uncertainty about what you need. Perhaps if you provided a circuit with dependent sources that specifically highlight your questions, it may help me better?...
View ArticleAnswer by periblepsis for Thevenin`s Theorem (Thevenin`s resistance)
I can't say if it will help you, since each of us have sometimes very different ways of thinking about the world we've found helpful, but perhaps try this idea. Imagine applying a \$1\:\text{A}\$...
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Answer by periblepsis for Thevenin theorem conditions and inquiries?
First off, they are trying to get you to use superposition methods. (I'd avoid that step and go directly to the solution.) Second, they write elsewhere, as you quote, "Alternatively, the dependent...
View ArticleComment by periblepsis on A new model for the bipolar transistor (BJT)
I've a simple request. It looks overcomplicated --- so much so that motivation to apply time is flagging. What would make me more interested would be seeing it get within 1%, quantitatively, of the...
View ArticleComment by periblepsis on Start-up Current for MCU
@John Can you arrange things so that the initial current is largely supplied by a capacitor during this short start period? And this really sounds like a job for an MSP430, looking through your writing...
View ArticleComment by periblepsis on How do you use matrices to solve circuit analysis...
HFTfE, It's there, in fact, that you can see both KCL and KVL, and how they are each inseparably connected facets of a larger picture, and all of it as a simultaneous picture. This allows insights you...
View ArticleComment by periblepsis on Is this question impossible to solve using the...
Can we at least see what you tried to do? What equations did you produce, that failed you? How can we help you find what you missed if you don't present how it is that you got 2 equations and 3...
View ArticleComment by periblepsis on Am I correctly solving this circuit with Ebers-Moll?
nuggethead, Is that 10fA or 1fA for the model saturation current? You might mean \$1\cdot 10^{-15}\$ or you might mean `10E-15' which is \$10\cdot 10^{-15}\$. I am not sure. Also, your ln() function...
View ArticleComment by periblepsis on Finding total resistance?
R2 is parallel to R3. R4 is parallel to R6. So I find 500 + ((330||500)+220) || (750||330) which equals 648.116584. I don't see any need for delta-y.
View ArticleComment by periblepsis on Battery supply and tuning of a Bulova Accutron watch
I remember, decades ago, having a conversation with an expert on this topic. He knew way more than he shared with me. But the gist of what I got is that these are not designed by run-of-the-mill...
View ArticleComment by periblepsis on Thevenin and Norton shortcuts
@dareen I've added another option. I can think of a few more without any effort. Hopefully, someone else will provide those.
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Answer by periblepsis for Is this question impossible to solve using the...
You know the following is true, given that you were able to already calculate that \$i_3=15\:\text{mA}\$:Here's an LTspice schematic that replicates yours:Note that I can set \$v_3\$ to anything from...
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Answer by periblepsis for Am I correctly solving this circuit with Ebers-Moll?
You can ignore the reverse-biased BC junction diode. So the injection version schematic boils down to:simulate this circuit– Schematic created using CircuitLabInjection version model, less the...
View ArticleComment by periblepsis on Weird simulation results with BJT NPN transistor
Daniel, Your question is pretty good. It tells me that you are experimenting and thinking about the results you are uncovering. This is one of the earmarks of a scientific mind and too rare,...
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Answer by periblepsis for Weird simulation results with BJT NPN transistor
qualitative explanationI just recently wrote about how to use a version of the Ebers-Moll model to make predictions for cases like this. Your circuit was put into saturation when you added the...
View ArticleComment by periblepsis on Why two types of critically damped response...
@Kuba It's the seventh edition. How can they keep seeing this text that keeps screaming out for improvement as it obviously does so loudly? And I'm sure a few grad students involved in editing must...
View ArticleComment by periblepsis on LTspice result does not match manual I-V plot for...
@vgeng Just because your x-axis reads negative at some node with respect to ground doesn't mean LTspice is then forced to interpret forward biased diode current as negative, too. For example, without...
View ArticleComment by periblepsis on How to eliminate the ground loops?
@Curious As gen_geek points out, your ground trace shows 50 Hz, but it appears differentiated -- spiking first upward and then downward -- as if capacitance is involved. No answers to offer. But wanted...
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