Common Source Amplifier | Analog Circuits | NerdyBug | 2025

Hey, Fellow Nerds! In this video, we dive deep into the Common Source Amplifier — one of the most fundamental and powerful building blocks in analog circuit design. We’ll explore the common source configuration in detail, including its small signal model, how to calculate voltage gain, and the role of source degeneration in improving performance. You'll also learn how to compute both input and output impedance with intuition, not just formulas. We’ll break down different biasing techniques like fixed bias, voltage divider bias, and self bias, and how each one affects amplifier behavior. Oh — and yes, we’ll talk about the diode-connected load and why it’s such a big deal in MOSFET circuits. Whether you're building intuition or solving problems, this video has your back. 🔥Full series: https://youtube.com/playlist?list=PLtQhvtIfWz_9_2R6iYs-M_NtOow1l_Anr&si=oK4knqN73WlcA3jU 🔥Grab your free notes 👉 https://www.nerdybug.in 📅 Chapters: 00:00:00 Introduction 00:00:19 Common source configuration 00:01:05 Amplification 00:04:24 Small Signal Model 00:06:05 Case 1: Voltage Gain ignoring channel length modulation 00:07:54 Case 1: Input and output impedances ignoring channel length modulation 00:11:30 Case 2: Voltage Gain including channel length modulation 00:13:32 Case 2: Input and output impedances including channel length modulation 00:14:04 Case 3: Intrinsic gain of a MOSFET amplifier 00:16:24 Case 4: Adding degeneration 00:28:47 Case 5: With bypass capacitor 00:30:30 MOSFET as a diode connected load 00:35:00 Example Problem 00:36:18 Biasing Techniques 00:37:39 Example Problem 🔔 Stay Connected: Subscribe: https://www.youtube.com/@NerdyBugNB?sub_confirmation=1 Instagram: https://instagram.com/thenerdybug Facebook: https://www.facebook.com/thenerdybug/ Join the Nerd Squad: https://t.me/+kEzUO7v6_HBjOGJl Visit our website: https://www.nerdybug.in 💬 Comments and Feedback: Got questions or suggestions? Drop them in the comments below! We’d love to hear from you. Do let us know if you enjoy the signals and systems lectures. Thank you for watching! If you found this video helpful, don’t forget to like, share, and subscribe. See you in the next video! #AnalogCircuits #NerdyBug #engineeringstudent