Eddynetweb: Starting 3.1 notes on MOSFET.

2022-04-12T00:28:21Z

Starting 3.1 notes on MOSFET.

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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 3.1 ==

What is a '''MOSFET'''?
* Stands for: Metal Oxide Semiconductor Field Effect Insulator.
* Yay!

See Figure 3a.

Has 3 sides:
* Gate, Drain, and Source
* The gate current is always 0 (Ig = 0).
* It is a symmetrical device (drain as source and vice versa).
* Length of channel is typically 0.03um to 1um
* Width of channel is typically 1um to 100um.
* Gate current is typically 0mA (10^-15mA)
* Drain voltage in position...

Threshold Voltage (Vt)
* At which a sufficient number of mobile electrons accumulate in the channel region to form a conducting channel.

Effective Voltage (or Overdrive Voltage)
* Vov = Vgs - Vt

Additional formulas to consider:
* Kn' = UnCox = Process Transconductance Parameter
** Un = Electron mobility
** Cox = Oxide capacitance
** Kn = MOSFET transconductance parameter = Kn'[w/L]
* r_DS = Channel Resistance = [1/g_DS] = [1/[UnCox][w/L][Vgs-Vt]]
* At V_DS, the channel is going to be deepest at the source and shallower at the drain.
* Channel resistance is inversely proportional to the gate voltage.

* Channel pinch off:
* The zero depth of the channel at the drain ends because of V_DS = V_GS - V_E
** If V_GS < Vtn then no channel, so transistor is working in cut off region (I_D = 0)

* MOSFET operation
** Tniode region
** Saturation region

Now we'll cover (B) Common Emitter Current gain:
* <math>B=\frac{I_{c}}{I_{b}}</math>
* 50 < B < 200

...and (Alpha) Common Base Current Gain:
* <math>Alpha = \frac{B}{B+1} = \frac{I_{c}}{I_{e}}</math>

=== Header 2 ===

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

===Assignment 1.1===

We'll take this <math>x_{3}=\frac{9}{3}</math> and plug it into <math>2x_{2}+x_{3}=5</math> to find x<sub>2</sub>:

<math>
\begin{align}
2x_{2}+x_{3}=5 \\
x_{3}=\frac{9}{3} \\
\text{Plug in } x_{3}=\frac{9}{3} \text{ into } 2x_{2}+x_{3}=5 \text{:} \\
2x_{2}+\frac{9}{3}=5 \\
2x_{2}=2 \\
x_{2}=1
\end{align}
</math>

ECE492 Section 3 Notes - Revision history

Eddynetweb: Starting 3.1 notes on MOSFET.