Transistors & Discrete Amplifiers

Transistors & Discrete Amplifiers: BJT Fundamentals: Operation, Regions & Models, BJT Biasing, Load Lines & Stability, BJT Amplifier Configurations: CE, CB, CC, Darlington & Cascode, JFET & MOSFET Fundamentals, FET Biasing & Amplifiers: CS, CG, CD, Cascode & Active Loads, Small-Signal Analysis & the Miller Effect, Frequency Response, Bode Plots & Bandwidth.

• BJT Fundamentals: Operation, Regions & Models — How the bipolar junction transistor works. Learn NPN and PNP structures, emitter/base/collector roles, carrier injection and transport, operating regions (forward-active, cutoff, saturation, reverse-active), current relations (I_E = I_C + I_B, β, α), V_BE and its exponential law, output characteristics and the Early effect, transconductance g_m, r_π and r_o, transition frequency f_T, the Ebers–Moll large-signal model, hybrid-π and T small-signal models, and BJT switching (saturation, storage time) — with Python computing small-signal parameters and sizing a saturated switch.
• BJT Biasing, Load Lines & Stability — Setting a stable operating point. Learn the Q-point and DC load line, fixed (base) bias, collector-feedback bias, emitter bias, voltage-divider bias with emitter resistor, two-supply bias and current-source bias, why emitter degeneration stabilises I_C, stability against β, V_BE and temperature, thermal runaway, choosing the Q-point for maximum symmetrical swing, and a complete step-by-step design with standard resistor values — with Python designing a divider-biased stage and testing it at β = 100 and 300.
• BJT Amplifier Configurations: CE, CB, CC, Darlington & Cascode — The three basic transistor amplifiers and their combinations. For each — common emitter, common base and common collector (emitter follower) — learn the schematic, biasing, small-signal model, voltage/current/power gain, phase, input and output resistance, frequency behaviour, practical uses and limitations; then emitter degeneration and bypassing, collector loading, and compound stages (Darlington, Sziklai, cascode) — with Python computing gains and impedances for bypassed and degenerated CE stages and an emitter follower.
• JFET & MOSFET Fundamentals — Voltage-controlled transistors. Learn the field-effect concept, JFET structure, pinch-off, I_DSS, V_GS(off) and the Shockley equation; MOSFET structure (gate oxide, channel, body, body diode), enhancement vs depletion, NMOS vs PMOS, threshold voltage, regions (cutoff, triode/linear, saturation, subthreshold), the square law and channel-length modulation, key parameters (V_TH, R_DS(on), g_m, g_mb, r_o, C_gs, C_gd, C_ds, Q_g, Q_gd, Q_oss) and switching loss — and why 'saturation' means opposite things for BJTs and MOSFETs — with Python computing JFET/MOSFET currents, g_m, R_DS(on) and switching losses.
• FET Biasing & Amplifiers: CS, CG, CD, Cascode & Active Loads — Amplifying with FETs. Learn FET bias schemes (fixed gate, self-bias for JFETs, voltage-divider gate bias, current-source bias, source degeneration), the common-source amplifier and its gain with resistive, active and current-source loads, source degeneration, the common-gate stage, the common-drain (source follower) buffer and body effect, the cascode for high gain and bandwidth, and a comparison of topologies by input/output impedance, gain, phase and application — with Python computing CS, degenerated CS, follower and cascode gains.
• Small-Signal Analysis & the Miller Effect — The linear toolkit behind amplifier design. Learn the operating point and linearisation, incremental models, transconductance, input and output resistance, voltage/current/power gain, Thevenin/Norton small-signal equivalents, BJT hybrid-π and T models, MOSFET models with g_m, g_mb and r_o, device capacitances (C_π, C_µ, C_gs, C_gd), the Miller theorem and effective input capacitance, pole estimation and bandwidth limits, and the transition frequency f_T — with Python computing the Miller capacitance, input and output poles and f_T of a CE stage.
• Frequency Response, Bode Plots & Bandwidth — How gain and phase change with frequency. Learn transfer functions, poles and zeros, low-frequency response from coupling and bypass capacitors, midband gain, high-frequency response from device capacitances, corner frequencies and time constants, bandwidth and gain-bandwidth product, dominant-pole behaviour, cascaded poles, and drawing Bode magnitude and phase plots (slopes of ±20 dB/decade, phase contributions, decades and octaves) — with Python computing a bandpass amplifier's Bode magnitude, coupling-capacitor size and cascaded bandwidth.