63.3. Introduction

Dear students, welcome back to our online NPTEL certification course on Analog Electronic Circuit. Myself, Pradip Mandal from E and EC department of IIT Kharagpur. Today we are going to talk about Multi Transistor Amplifiers; namely, in fact this is continuation of our previous lectures. So, today we will be talking about Numerical Examples of Cascode Amplifiers.

In this part of the lecture, the instructor welcomes students back to the course, introducing himself and providing an overview of the day's topic. He mentions that the focus will be on multi transistor amplifiers, specifically cascode amplifiers. This indicates that the lecture follows a series of previous discussions, emphasizing continuity in learning and exploration of the subject. The emphasis on numerical examples suggests practical engagement with theoretical concepts.

Think of learning about amplifiers like cooking. After learning the basic recipes, such as making a simple soup (analogous to previous lessons on basic amplifiers), the instructor now guides students through complex dishes (like cascode amplifiers) using structured techniques (numerical examples) that enhance their understanding of how these complex dishes are created and what makes them unique.

So, the coverage of a today’s lecture it is primarily cascode amplifier using BJT and cascode amplifiers using MOSFET. We do have two very in depth numerical problems we have said, and most likely we will be discussing on this BJT based on cascode amplifier.

Here, the instructor outlines the specific content for the lecture. He indicates that the primary focus will be on two types of cascode amplifiers: those using BJTs (Bipolar Junction Transistors) and MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). He specifies that there will be an emphasis on practical numerical problems, thus reinforcing the theoretical understanding through hands-on applications. This approach allows students to see the real-world implications of the concepts they are studying.

Imagine a workshop where students are learning to build machines. The instructor is explaining how to create two types of engines (BJT and MOSFET cascode amplifiers) and plans to provide hands-on exercises that will help students learn how these engines work practically. Just like in a workshop, theory is combined with application to make the learning process more effective.

So, that gives you some idea that why we go for this cascode amplifier compared to a simple CE amplifier.

In this statement, the instructor introduces the rationale behind using cascode amplifiers over simpler common-emitter (CE) amplifiers. The cascode amplifier configuration often provides benefits such as improved bandwidth and reduced distortion, making it a more efficient choice in many applications. Understanding this distinction highlights the importance of selecting appropriate amplifier designs based on specific criteria or needs.

Choosing an amplifier design can be compared to selecting the right tool for a job. For instance, if you're assembling furniture, using a specialized screwdriver may be more effective than using a basic one, similar to how a cascode amplifier offers enhanced performance compared to a standard common-emitter amplifier. The right choice leads to better results.

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