Quiz2

What is the primary assumption in small-signal analysis of BJTs?

• The transistor operates in the cutoff region
• The transistor operates in the saturation region
• The transistor operates in the active region
• The transistor operates in the breakdown region

In small-signal modeling, what parameter represents the small-signal current gain of a BJT?

• ror_o
• gmg_m
• β\beta
• VBEV_{BE}

What is the small-signal transconductance (gmg_m) of a BJT defined as?

• gm=IC/VBEg_m = I_C/V_{BE}
• gm=IE/VBEg_m = I_E/V_{BE}
• gm=IC/VCEg_m = I_C/V_{CE}
• gm=IC/VTg_m = I_C/V_T

In the hybrid-pi model, what component represents the small-signal base-emitter resistance?

• ror_o
• rπr_\pi
• gmg_m
• β\beta

The small-signal output resistance (ror_o) in the hybrid-pi model is given by:

• ro=VA/ICr_o = V_A / I_C
• ro=VC/ICr_o = V_C / I_C
• ro=β/gmr_o = \beta/g_m
• ro=1/gmr_o = 1/g_m

Which of the following factors affect the small-signal voltage gain of a common-emitter amplifier?

• Load resistance
• Transconductance (gmg_m)
• Intrinsic emitter resistance (rer_e)

The input impedance of a common-emitter amplifier without emitter degeneration is approximately:

• ror_o
• rπr_\pi
• 1/gm1/g_m
• βro\beta r_o

The voltage gain of a common-emitter amplifier with a resistive load can be approximated as:

• gmRCg_m R_C
• RC/rπR_C / r_\pi
• βRC\beta R_C
• 1/gmRC1/g_m R_C

How does adding an emitter resistor (RER_E) affect the voltage gain in a common-emitter amplifier?

• Increases the gain
• Decreases the gain
• Has no effect on gain
• Makes the gain infinite

In small-signal analysis, which model is most commonly used for high-frequency BJT analysis?

• Hybrid-pi model
• T-model
• Large-signal Ebers-Moll model
• Small-signal Thévenin model