2: Bipolar Transistors
- Page ID
- 88488
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- 2.1: Intro to Bipolar Resistors
- This page details the structure and operation of NPN bipolar transistors, consisting of an emitter (n-type), base (p-type), and collector (lightly doped n-type). It covers biasing configurations crucial for functionality, particularly forward active biasing, which involves forward biasing the emitter-base junction and reverse biasing the base-collector junction.
- 2.2: Transistor Equations
- This page covers key performance metrics for transistors, focusing on emitter injection efficiency (\(\gamma\)) and base transport factor (\(\alpha_T\)). It explains how \(\gamma\) reflects junction doping effects on electron currents, while \(\alpha_T\) pertains to electron movement through the base influenced by geometry. Additionally, it establishes the connection between base and collector currents, leading to the definition of current gain (\(\beta\)).
- 2.3: Transistor I-V Characteristics
- This page explains the current-voltage relationships in bipolar transistors, focusing on the collector-base (CB) and emitter-base (EB) junctions. It details the operational characteristics under various bias states, noting that in reverse bias, the transistor acts like a diode.
- 2.4: Common Emitter Models
- This page explains the common emitter configuration of a transistor, contrasting it with the common base model. It details the diode between the base and emitter, and a current-controlled current source between the collector and emitter. While \(V_{BE}\) follows the exponential principle, the saturation current varies due to the configuration. The aim is to enhance circuit analysis, although the nonlinearity indicates a requirement for a simplified linear model for practical use.
- 2.5: Small Signal Models
- This page explores the development of a linear model for diode behavior through the application of bias and signal voltages. It details the total current as a combination of bias and signal currents, aiming to establish a linear relationship between the small signal voltage and current.
- 2.6: Small Signal Model for Bipolar Transistor
- This page explores the small signal model of a common emitter transistor, focusing on its behavior with small AC signals compared to large DC currents. It derives the equivalent small signal resistance, \(r_{\pi}\), and discusses how base width modulation affects collector current \(I_C\) and introduces Early Voltage \(V_A\). Additionally, it addresses the transconductance model and the implications of breakdown in bipolar transistors.