Gain Circles - Part I — Lesson 5

This lesson covers the amplifier gain and stability. It delves into the different types of gain, with a special emphasis on transducer gain, and the challenges associated with designing gamma. The lesson also discusses the concept of unilateral case design, and the conditions for unconditional stability. It further explains the process of impedance matching and the concept of a unilateral approximation figure of merit. The lesson uses illustrative examples and diagrams to explain complex concepts like gain circles, stability circles, and the locus of gamma values.

Video Highlights

01:42 - Design for the unilateral case and Unconditional stable case
02:25 - Unconditional stable case
06:49 - Potentially unstable case
08:15 - Two port diagram and stability
15:21 - Explanation of the impedance matching
18:34 - Unilateral approximation figure of merit.

Key Takeaways

- Transducer gain is the most practical definition of gain, but it presents challenges in independent design of gamma F and gamma L.
- The unilateral case, where S12 equals 0, simplifies the definition of transducer gain.
- Gain circles and stability circles play a crucial role in amplifier design, with different characteristics in potentially unstable and unconditionally stable cases.
- Impedance matching is essential for achieving desired gain, and the unilateral approximation figure of merit can determine whether this approximation is valid.