Hi all,
The other day at work I was talking to one of the EEs about BJTs; although I studied them, I forgot how to interpret what it meant on a circuit diagram (Im not an EE). After it was explained to me, I started to poke into the specific details of how it worked, and the EE told me he didnt remember. Now I did learn this stuff because I took one of the courses in the long series of device physics. I actually liked the class, found it interesting, and went back to review things (and it is made easy because the book is such an easy read Semiconductor Device Fundamentals by Robert F. Pierret. It isnt a pretty book with photos all over, but he explains things well).
Im reading about the Density of States at the moment (yup going back to the basics before I jump to BJT actually, it is quite refreshing to read theory for me; it is like a nice break from work) and it carries units of #/ (Volume * Energy). I understand #/Volume number of whatever we are counting per a given volume, and #/Energy, but I have never been able to fully understand # /(Volume*Energy). How do I interpret that? This is actually an annoyance of mine because Ill come across many situations and I cant seem to fully grasp a value where dimensional analysis results in multiple parameters in the denominator.
The closest I get to bending around this is thinking of acceleration: m/s^2. The way I get around it is thinking of it as v/s, and then it makes sense to me. I can do this with a few other parameters, but once I face something that I havent spent a lot of time with, and isnt as intuitive to think about, I always get stuck with how to interpret it in my head. I suppose that I try to build something I understand into its own container (ie: v=m/s), and then contain that again as I further understand it.
Does this interpretation work (this is how I often think and approach things, so any validation, or suggestions, and critiques can only help!): Given a sea of states, I , in a spatially arbitrary location, isolate a unit volume of states, which will give me the direct number of states per volume; then within that volume, split up the available states based on the energy levels that are found (which should make sense since the energies are only available at discrete levels).
Im wondering if anyone has some insight and can crack this apart for me, or give me a better explanation of how to look at values where a dimensional analysis reveals multiple parameters (L,M,T or any combination) in the denominator. I guess writing this out and thinking about it has helped to clear it up for me (unless I understand it wrong), but to get any more insight is always helpful.
The other day at work I was talking to one of the EEs about BJTs; although I studied them, I forgot how to interpret what it meant on a circuit diagram (Im not an EE). After it was explained to me, I started to poke into the specific details of how it worked, and the EE told me he didnt remember. Now I did learn this stuff because I took one of the courses in the long series of device physics. I actually liked the class, found it interesting, and went back to review things (and it is made easy because the book is such an easy read Semiconductor Device Fundamentals by Robert F. Pierret. It isnt a pretty book with photos all over, but he explains things well).
Im reading about the Density of States at the moment (yup going back to the basics before I jump to BJT actually, it is quite refreshing to read theory for me; it is like a nice break from work) and it carries units of #/ (Volume * Energy). I understand #/Volume number of whatever we are counting per a given volume, and #/Energy, but I have never been able to fully understand # /(Volume*Energy). How do I interpret that? This is actually an annoyance of mine because Ill come across many situations and I cant seem to fully grasp a value where dimensional analysis results in multiple parameters in the denominator.
The closest I get to bending around this is thinking of acceleration: m/s^2. The way I get around it is thinking of it as v/s, and then it makes sense to me. I can do this with a few other parameters, but once I face something that I havent spent a lot of time with, and isnt as intuitive to think about, I always get stuck with how to interpret it in my head. I suppose that I try to build something I understand into its own container (ie: v=m/s), and then contain that again as I further understand it.
Does this interpretation work (this is how I often think and approach things, so any validation, or suggestions, and critiques can only help!): Given a sea of states, I , in a spatially arbitrary location, isolate a unit volume of states, which will give me the direct number of states per volume; then within that volume, split up the available states based on the energy levels that are found (which should make sense since the energies are only available at discrete levels).
Im wondering if anyone has some insight and can crack this apart for me, or give me a better explanation of how to look at values where a dimensional analysis reveals multiple parameters (L,M,T or any combination) in the denominator. I guess writing this out and thinking about it has helped to clear it up for me (unless I understand it wrong), but to get any more insight is always helpful.
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