Part III: Analog Electronics
Amplification, operational amplifiers, and feedback — the building blocks of analog signal processing from audio circuits to precision instrumentation.
Analog Signal Chain
What You Will Learn
Analog electronics is concerned with circuits that process continuously varying electrical signals. Unlike digital circuits, which deal in discrete voltage levels, analog circuits work with the full spectrum of possible voltages and currents. The goal is always to faithfully amplify, filter, integrate, or otherwise transform these signals with minimal distortion and noise.
The central relationship is the gain equation: \( A_v = V_{out}/V_{in} \). From simple transistor stages to precision op-amp circuits, every analog building block can be characterized by its gain, input impedance \( Z_{in} \), output impedance \( Z_{out} \), and frequency response \( A_v(j\omega) \).
Negative feedback — described by the closed-loop gain \( A_f = A/(1 + A\beta) \) — is the master technique of analog design, simultaneously reducing distortion, stabilizing gain, extending bandwidth, and setting impedances to desired values.
Key Equations of Part III
Chapters in Part III
Amplifier Fundamentals
Voltage and current gain, input/output impedance, common-emitter and common-source amplifiers, small-signal models, frequency response, and gain-bandwidth product.
Operational Amplifiers
Ideal op-amp golden rules, inverting and non-inverting configurations, summing amplifier, difference amplifier, integrator, and differentiator circuits.
Feedback & Stability
Negative feedback theory, loop gain, closed-loop gain, Barkhausen criterion, Bode stability analysis, gain margin, phase margin, and the Nyquist criterion.