ECE 346 EXAM 3 QUESTIONS WITH VERIFIED SOLUTIONS LATEST UPDATE 2026
BJT - Answers Device using two pn junctions for amplification
Emitter, Base, Collector - Answers Emitter injects, base controls, collector collect carriers
Common base - Answers Configuration: base is reference (input at emitter, output at collector)
Common emitter - Answers Configuration: emitter is reference (most used, high gain)
Active mode - Answers Forward EB, reverse CB → amplification
Saturation mode - Answers Both junctions forward → fully ON
Cutoff mode - Answers Both junctions reverse → OFF
Inverted mode - Answers Roles of emitter and collector reversed (rare use)
Quasineutral base width - Answers Base region where carriers diffuse (no electric field)
Emitter efficiency - Answers How well emitter injects majority carriers
Base transport factor - Answers Fraction of carriers reaching collector
Common base gain (α) - Answers α = IC/IE
Common emitter gain (β) - Answers β = IC/IB
Performance parameters - Answers Metrics describing BJT efficiency and gain
Ebers-Moll model - Answers Large-signal model using diode currents
Base-width modulation - Answers Base width changes with voltage → affects current
Early effect - Answers Increase in IC due to base-width shrinking
Punch-through (BJT) - Answers Depletion regions meet → loss of control
Gummel plot - Answers Log plot of IC and IB vs voltage
Source - Answers Terminal where carriers enter the channel
Drain - Answers Terminal where carriers leave the channel
Gate - Answers Controls channel using electric field (gate voltage)
Channel - Answers Conductive path between source and drain
Pinch-off - Answers Channel charge goes to zero near drain → current saturates
Transconductance - Answers gm = dID/dVG (gate control of current)
MMIC - Answers Microwave integrated circuit for high-frequency signals
D-MESFET - Answers Depletion-mode MESFET (normally ON)
E-MESFET - Answers Enhancement-mode MESFET (normally OFF)
Long channel - Answers Channel where short-channel effects are negligible
Short channel - Answers Channel where effects (velocity saturation, etc.) matter
Bulk - Answers Semiconductor body/substrate
Block charge diagram - Answers Diagram showing charge distribution in MOS
Accumulation - Answers Majority carriers accumulate at surface
Flat band (MOS) - Answers No band bending in semiconductor
Depletion (MOS) - Answers Majority carriers removed → fixed charge remains
Inversion - Answers Surface becomes opposite type → channel forms
Weak inversion - Answers Below threshold, current is exponential
Strong inversion - Answers Above threshold, stable channel exists
Surface potential - Answers Voltage controlling band bending at surface
Oxide capacitance - Answers Capacitance of oxide layer in MOS
Saturation (MOSFET) - Answers VD ≥ VG − VT → current ~ constant
Linear (triode) region - Answers VD < VG − VT → resistive behavior
Threshold voltage - Answers Gate voltage where strong inversion begins
Subthreshold characteristics - Answers Exponential current below threshold (diffusion dominated)
Flat-band voltage - Answers Gate voltage that makes bands flat
Interfacial traps - Answers Defects at oxide-semiconductor interface that trap charge
Trapped charge - Answers Charge trapped in oxide or interface
BJT - Answers Device using two pn junctions for amplification
Emitter, Base, Collector - Answers Emitter injects, base controls, collector collect carriers
Common base - Answers Configuration: base is reference (input at emitter, output at collector)
Common emitter - Answers Configuration: emitter is reference (most used, high gain)
Active mode - Answers Forward EB, reverse CB → amplification
Saturation mode - Answers Both junctions forward → fully ON
Cutoff mode - Answers Both junctions reverse → OFF
Inverted mode - Answers Roles of emitter and collector reversed (rare use)
Quasineutral base width - Answers Base region where carriers diffuse (no electric field)
Emitter efficiency - Answers How well emitter injects majority carriers
Base transport factor - Answers Fraction of carriers reaching collector
Common base gain (α) - Answers α = IC/IE
Common emitter gain (β) - Answers β = IC/IB
Performance parameters - Answers Metrics describing BJT efficiency and gain
Ebers-Moll model - Answers Large-signal model using diode currents
Base-width modulation - Answers Base width changes with voltage → affects current
Early effect - Answers Increase in IC due to base-width shrinking
Punch-through (BJT) - Answers Depletion regions meet → loss of control
Gummel plot - Answers Log plot of IC and IB vs voltage
Source - Answers Terminal where carriers enter the channel
Drain - Answers Terminal where carriers leave the channel
Gate - Answers Controls channel using electric field (gate voltage)
Channel - Answers Conductive path between source and drain
Pinch-off - Answers Channel charge goes to zero near drain → current saturates
Transconductance - Answers gm = dID/dVG (gate control of current)
MMIC - Answers Microwave integrated circuit for high-frequency signals
D-MESFET - Answers Depletion-mode MESFET (normally ON)
E-MESFET - Answers Enhancement-mode MESFET (normally OFF)
Long channel - Answers Channel where short-channel effects are negligible
Short channel - Answers Channel where effects (velocity saturation, etc.) matter
Bulk - Answers Semiconductor body/substrate
Block charge diagram - Answers Diagram showing charge distribution in MOS
Accumulation - Answers Majority carriers accumulate at surface
Flat band (MOS) - Answers No band bending in semiconductor
Depletion (MOS) - Answers Majority carriers removed → fixed charge remains
Inversion - Answers Surface becomes opposite type → channel forms
Weak inversion - Answers Below threshold, current is exponential
Strong inversion - Answers Above threshold, stable channel exists
Surface potential - Answers Voltage controlling band bending at surface
Oxide capacitance - Answers Capacitance of oxide layer in MOS
Saturation (MOSFET) - Answers VD ≥ VG − VT → current ~ constant
Linear (triode) region - Answers VD < VG − VT → resistive behavior
Threshold voltage - Answers Gate voltage where strong inversion begins
Subthreshold characteristics - Answers Exponential current below threshold (diffusion dominated)
Flat-band voltage - Answers Gate voltage that makes bands flat
Interfacial traps - Answers Defects at oxide-semiconductor interface that trap charge
Trapped charge - Answers Charge trapped in oxide or interface
