I'm reviewing my electronic basic fundamentals and now I'm trying to tackle questions that I never bothered to ask while I was in the classroom. (You might have noticed some of my other threads) I actually know some things, but there are huge gaps in my knowledge.
It is said that there are three BJT configurations namely, common collector, common base, common emitter.
- Sometimes the drawings of these configurations are shown with two sources, yet in actual practice most of the time BJTs in circuit have only one supply so I find this confusing. Why is it that sometimes it is shown with two sources and why sometimes with only one?
- Sometimes drawings of these configurations focus only on which terminal is being grounded: if it's grounded emitter then it's common emitter, etc. And highlighted is the input side and output side, but where are the voltage sources connected? There are actually two voltage sources for it to start to operate?
- We also have different kinds of biasing modes such as voltage feedback, voltage divider, etc, but what is the difference between the modes of bias and the configurations? Can you have a fixed bias, emitter stabilized, etc for common base, then have a fixed bias, emitter stabilized, etc for a common collector, then have a
a fixed bias, emitter stabilized, etc for a common emitter? So confusing.
- I know how to tell how diodes are biased, but not how a transistor is biased. I am having difficulty in telling whether the BE junction is forward or reversed and whether the BC junction is forward or reversed, especially in large circuits such as the internal circuitry of Integrated Circuits that are composed of so many transistors.. And this problem is carrying on even to my analysis of thyristors, UJTs, etc which are just extensions of the BJT concept, for instance with the SCR it is just approximate to an NPN and a PNP, but I am having trouble understanding basics of BJT concept in the first place so I don't know what to make of the SCR's BJT equivalent unless someone explains it to me.
- Also I am aware about the conditions for active, saturation, and cut-off, operating regions and what those regions imply, I just need to master how to determine the biasing so that I can conclude what regions the transistors are in. The books focus on how the transistor is biased in order to determine the region of operation yet here: https://www.electronicspoint.com/resources/how-a-bjt-transistor-works-base-current-version.37/ there is no mention of how the transistor is biased. (He did say that his guide is under construction).
I want to master the concept of BJT, so that I can extend that mastery to the analysis of other thyristors and devices based on the BJT, and to the analysis of the internal circuitry inside ICs. What I would like to know is how to merely look at the BJT equivalent of an IC or of a thyristor, and without having been told anything about the IC or thyristor but only on the BJT equivalent alone, be able to deduce its function and limitations.
And if you have general or specific advice/explanations regarding any of these matters it would be appreciated. I am trying to bridge the gap from being a carefree student to being a serious, responsible engineer.
It is said that there are three BJT configurations namely, common collector, common base, common emitter.
- Sometimes the drawings of these configurations are shown with two sources, yet in actual practice most of the time BJTs in circuit have only one supply so I find this confusing. Why is it that sometimes it is shown with two sources and why sometimes with only one?
- Sometimes drawings of these configurations focus only on which terminal is being grounded: if it's grounded emitter then it's common emitter, etc. And highlighted is the input side and output side, but where are the voltage sources connected? There are actually two voltage sources for it to start to operate?
- We also have different kinds of biasing modes such as voltage feedback, voltage divider, etc, but what is the difference between the modes of bias and the configurations? Can you have a fixed bias, emitter stabilized, etc for common base, then have a fixed bias, emitter stabilized, etc for a common collector, then have a
a fixed bias, emitter stabilized, etc for a common emitter? So confusing.
- I know how to tell how diodes are biased, but not how a transistor is biased. I am having difficulty in telling whether the BE junction is forward or reversed and whether the BC junction is forward or reversed, especially in large circuits such as the internal circuitry of Integrated Circuits that are composed of so many transistors.. And this problem is carrying on even to my analysis of thyristors, UJTs, etc which are just extensions of the BJT concept, for instance with the SCR it is just approximate to an NPN and a PNP, but I am having trouble understanding basics of BJT concept in the first place so I don't know what to make of the SCR's BJT equivalent unless someone explains it to me.
- Also I am aware about the conditions for active, saturation, and cut-off, operating regions and what those regions imply, I just need to master how to determine the biasing so that I can conclude what regions the transistors are in. The books focus on how the transistor is biased in order to determine the region of operation yet here: https://www.electronicspoint.com/resources/how-a-bjt-transistor-works-base-current-version.37/ there is no mention of how the transistor is biased. (He did say that his guide is under construction).
I want to master the concept of BJT, so that I can extend that mastery to the analysis of other thyristors and devices based on the BJT, and to the analysis of the internal circuitry inside ICs. What I would like to know is how to merely look at the BJT equivalent of an IC or of a thyristor, and without having been told anything about the IC or thyristor but only on the BJT equivalent alone, be able to deduce its function and limitations.
And if you have general or specific advice/explanations regarding any of these matters it would be appreciated. I am trying to bridge the gap from being a carefree student to being a serious, responsible engineer.
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