00 what to study

Topic 1: FET Basics & Characteristics

Sub-subtopic: Device Comparisons & Differences

• Theory: Write down the specific differences between BJT and FET. (2024, 2023, 2017, 2016) ✅ 2026-06-23
• Theory: Distinguish between p-channel and n-channel JFET. (2019, 2016) ✅ 2026-06-23
• Numerical/Sketch: Given $I_{DSS}$ and $V_P$ (e.g., $I_{DSS}=4mA,V_P=3V$), sketch the transfer characteristics of a p-channel JFET. (2019, 2016)

Sub-subtopic: Input Impedance & Physical Behavior

• Theory: Explain the reasons behind the higher input impedance of a FET. (2018) ✅ 2026-06-23
• Theory: Why is the input impedance of a MOSFET so high? Explain in brief. (2021, 2019) ✅ 2026-06-23

Sub-subtopic: MOSFET Theory & Construction

• Theory/Differences: Distinguish between depletion-type and enhancement-type MOSFETs. (2021, 2019, 2016) ✅ 2026-06-23
• Theory: Explain the construction and operation of a depletion-type MOSFET using necessary diagrams. (2016) ✅ 2026-06-23
• Theory: Construct an n-channel enhancement-type MOSFET and explain its basic operation. (2022) ✅ 2026-06-23

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Topic 2: FET DC Biasing Configurations

Sub-subtopic: Self-Bias Configuration

• Derivation: Prove terminal voltage equations for a JFET self-bias configuration with necessary diagrams, such as proving $V_D=V_{DD}-[]V_{RD}$ or $V_D=V_{DS}+V_S$. (2024, 2023, 2015) ✅ 2026-06-23
• Numerical: Given a self-bias circuit and its component values, use the appropriate transfer curve to calculate $I_{DQ}$, $V_{GSQ}$, $V_{DS}$, $V_D$, $V_G$, and $V_S$. (2018, 2017, 2016, 2015)

Sub-subtopic: Voltage-Divider Bias Configuration

• Theory: Explain the voltage divider biasing of a FET amplifier and consequently discuss the effect of the source resistor ($R_S$) on the resulting Q-point. (2021, 2018, 2017, 2015) ✅ 2026-06-23
• Numerical: Determine parameters like $I_{DQ}$, $V_{GSQ}$, $V_D$, $V_S$, $V_{DS}$, $V_G$, and $V_{DG}$ for voltage-divider JFET networks. (2023, 2021)

Sub-subtopic: Fixed-Bias Configuration

• Theory: Write down the differences between self-bias and fixed-bias configurations of FETs. (2016) ✅ 2026-06-23

Sub-subtopic: Other/General Biasing Problems

• Numerical: Determine $I_{DQ}$, $V_{GSQ}$, $V_D$, and $V_S$ for common-gate configurations. (2020)
• Numerical: Calculate $V_G$ and $V_{DS}$ for an n-channel JFET network given its operating points ($I_{DQ}$ and $V_{GSQ}$). (2022, 2019)

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Topic 3: FET AC Small-Signal Analysis

Sub-subtopic: Transconductance ($g_m$) & Output Resistance ($r_d$)

• Derivation/Theory: Derive the mathematical definition of transconductance ($g_m$) and explain the effect of drain current on the transconductance factor. (2023, 2020, 2018, 2017, 2016, 2015) ✅ 2026-06-23
• Derivation: Show mathematically that $g_m=g_{m0}[1-[]V_{GS}/V_P]$. (2015) ✅ 2026-06-23

Sub-subtopic: Common-Source Amplifiers (Self-Bias & Fixed-Bias)

• Derivation: Prove that for a self-bias FET configuration, the voltage gain increases by a factor of $(1+g_m{R}_S)$ when a bypass resistance $R_S$ is used. (2023, 2022, 2018, 2016) ✅ 2026-06-23
• Derivation: Derive the expression of voltage gain for a self-bias configuration with an unbypassed $R_S$ (e.g., proving $A_v\cong -g_m{R}_D/(1+g_m{R}_S)$). (2024, 2019) ✅ 2026-06-23
• Theory/Proof: For a self-bias JFET amplifier, show that the voltage gain with unbypassed $R_S$ is less than the voltage gain with bypassed $R_S$. (2015) ✅ 2026-06-23
• Numerical: Calculate AC parameters ($g_m$, $r_d$, $Z_i$, $Z_o$, $A_v$) with and without the internal output resistance ($r_d$) for Fixed-bias and Self-bias networks, and comment on the effect of $r_d$ on the voltage gain. (2023, 2022, 2021)
• Numerical/Design: Design a fixed-biased network to achieve a specific AC voltage gain of 10. (2022, 2019, 2018, 2015)

Sub-subtopic: Common-Gate Configuration

• Derivation: Prove that the voltage gain $A_v\cong g_m{R}_D$ for a common-gate JFET configuration. (2023, 2021, 2019, 2017)

Sub-subtopic: Source-Follower (Common-Drain) Configuration

• Derivation: Draw a JFET source-follower configuration and its AC equivalent circuit, and prove that $A_v\cong \frac{g_m{R}_S}{1+g_m{R}_S}$. (2019)
• Numerical: Given the DC operating points ($V_{GSQ}$ and $I_{DQ}$) of a source-follower network, determine $g_m$, $r_d$, Input Impedance ($Z_i$), Output Impedance ($Z_o$) with/without $r_d$, and Voltage Gain ($A_v$) with/without $r_d$. (2024, 2020, 2018, 2017, 2016)