ECE492 Section 1 Notes: Difference between revisions

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* Electrons are always in the valency band.  
* Electrons are always in the valency band.  
* In between, there is an energy gap, which is exactly 1.12eV (1eV = 1.602 * 10<sup>-19</sup>J).  
* In between, there is an energy gap, which is exactly 1.12eV (1eV = 1.602 * 10<sup>-19</sup>J).  
* Once electrons are in the conduction band, the semi-conductor will act as a conductor.
This entire class is based on semi-conductor materials.
=== What is a semiconductor? ===
It sometimes allow current, and sometimes it doesn't.
Semi-conductors only have '''4''' electrons in its outermost orbit.
* Carbon
* Silicon
* Germanium
* Lead
What's the best two?
* Silicon and Germanium
Consideration of Silicon:
* Silicon will acquire other silicon atoms to form a covalent bond.
Now let's take a Silicon atom:
* Take a pure silicon atoms and put energy to them: go from insulator to conductive properties, and electrons from the furthest orbit detach and jump to another position. 
* When electrons detach, it leaves a hole where it once was, that is viewed as a positive charge for clarity.
Doping: Adding impurity to a pure semiconductor material.
* Tri-Valent Impurity: majority of "holes" (positive charge), also know as P-type semiconductor.
* Penta-Valent Impurity: majority of electrons, also known as N-type semiconductor.
Let's take Aluminum for Tri-Valent example:
* Pair the Aluminum with Silicon atoms, knowing that Aluminum has an outer electron count of 3.
* Silicon will be bounded to the three outer Aluminum electrons, but 1 Silicon will be left.
Let's try Phosphorous for Penta-Valent example:
* Pair Phosphorous with Silicon atoms, knowing that Phosphorous has an outer electron count of 5.


===Assignment 1.1===
===Assignment 1.1===

Revision as of 19:17, 24 January 2022

Welcome! Notes for Spring 2022 Electronic Circuits course. Will make this more pretty as things evolve.

My goal is to make Electronic Circuits so easily digestible, you could teach a middle schooler. We'll see if this works.

Prologue

Hey how are you. I will insert something here later. :)

Section 1.1

We first need to consider the following materials:

  • Conductors
  • Insulators
  • Semiconductors

Consider the concept of the charge for Oxygen (O):

  • 8 protons around the nucleus
  • 8 electrons (two on the inner orbit, 6 on the outer orbit).

Let's look at the outer most orbit in context with a conductor:

  • There are two bands: valency and conduction.
  • Electrons are always in the valency band.
  • In between, there is an energy gap, which is approximately 0 (meaning electrons can move freely between valency band and conduction band).
  • That is the reason why conductive materials act as they do.

Let's look at the outer most orbit in the context of insulators:

  • There are two bands: valency and conduction.
  • Electrons are always in the valency band.
  • In between, there is an energy gap, which is very high (meaning electrons have a very hard time moving between the valency band and conduction band).
  • That is the reason insulators, are well, insulators (or their property is insulative).

Let's look at the outer most orbit in the context of semi-conductors:

  • There are two bands: valency and conduction.
  • Electrons are always in the valency band.
  • In between, there is an energy gap, which is exactly 1.12eV (1eV = 1.602 * 10-19J).
  • Once electrons are in the conduction band, the semi-conductor will act as a conductor.

This entire class is based on semi-conductor materials.

What is a semiconductor?

It sometimes allow current, and sometimes it doesn't.

Semi-conductors only have 4 electrons in its outermost orbit.

  • Carbon
  • Silicon
  • Germanium
  • Lead

What's the best two?

  • Silicon and Germanium

Consideration of Silicon:

  • Silicon will acquire other silicon atoms to form a covalent bond.

Now let's take a Silicon atom:

  • Take a pure silicon atoms and put energy to them: go from insulator to conductive properties, and electrons from the furthest orbit detach and jump to another position.
  • When electrons detach, it leaves a hole where it once was, that is viewed as a positive charge for clarity.

Doping: Adding impurity to a pure semiconductor material.

  • Tri-Valent Impurity: majority of "holes" (positive charge), also know as P-type semiconductor.
  • Penta-Valent Impurity: majority of electrons, also known as N-type semiconductor.

Let's take Aluminum for Tri-Valent example:

  • Pair the Aluminum with Silicon atoms, knowing that Aluminum has an outer electron count of 3.
  • Silicon will be bounded to the three outer Aluminum electrons, but 1 Silicon will be left.

Let's try Phosphorous for Penta-Valent example:

  • Pair Phosphorous with Silicon atoms, knowing that Phosphorous has an outer electron count of 5.


Assignment 1.1

We'll take this and plug it into to find x2: