38.1. Frequency Response of CE and CS Amplifiers (Contd.) (Part A)

Dear students, welcome back to this NPTEL online course on Analog Electronic Circuits. Myself Pradip Mandal from E and EC Department of IIT, Kharagpur. Today, we are going to continue the Frequency Response of Common Emitter and Common Source Amplifier and so it is primarily whatever the remaining topic, it was there we are going to cover today and will be mainly focusing on common emitter amplifier.

So, in the previous day we have discussed about common emitter amplifier with fixed bias and today we are going to discuss more about the self-biased common emitter amplifier.

In this portion, the instructor welcomes students and introduces the topic for the day, which is the Frequency Response of Common Emitter (CE) and Common Source (CS) amplifiers. They recap what was covered in the previous lecture, specifically focusing on the fixed bias common emitter amplifier. Today, the focus shifts to a different configuration known as the self-biased common emitter amplifier, indicating a progression in the understanding of amplifiers.

Think of this as learning how to make a recipe with the basic ingredients first (fixed bias), and now the chef is introducing a new method (self-bias) that allows for more flexibility and better results, like adjusting seasoning during cooking for optimal flavor.

So, in the previous week we have discussed about the frequency response of CE amplifier for which we have detail discussion about R-C and C-R circuit and then you know we have discussed about the common source amplifier particularly with circuit analysis.

Here, the instructor revisits the key elements discussed in prior lectures, specifically mentioning the frequency response of the common emitter amplifier and circuit analysis of the common source amplifier. This recap is important because it sets a foundation for the new content by reminding students of previous concepts like the R-C and C-R circuit configurations.

It’s like reviewing the rules of a game before moving on to a more advanced level. Before students can tackle a new challenge in amplifiers, they need to be comfortable with the groundwork they've already covered.

Likewise, for common emitter amplifier as I said that for fixed bias we have covered. So, circuit analysis portion it was covered before and today, we will be discussing about some numerical examples. But before that we are going to discuss about the frequency response of common emitter amplifier with self-bias arrangement.

In this segment, the instructor outlines that the lesson will include discussion points on previous circuit analysis while introducing new numerical examples for better understanding. The emphasis will be on understanding how to analyze the frequency response of the self-biased common emitter amplifier, which is crucial for practical applications in circuit design.

Imagine preparing a project report after gathering data. You review your previous findings and then show how these insights can inform new examples or real-world applications, just as the instructor plans to do with numerical examples.

So, we are going to start with the common emitter amplifier with self-biased and its corresponding circuit analysis. And later on of course, we will be going to discuss about numerical examples. From these numerical examples, we will get an idea that how to select the value of different capacitive components in the circuit.

The instructor indicates that the lesson will delve into circuit analysis for the self-biased common emitter amplifier and provide numerical examples, which are necessary for understanding the selection of capacitor values. This is essential for designing amplifiers that effectively control frequencies.

Think of this as a workshop where participants not only learn theory but also apply it practically. Just like in cooking classes, where students not only learn recipes (theory) but also prepare dishes (practice), leading to a better grasp of how to manipulate flavors and ingredients (capacitor values).

So, we need to just recapitulate some part of it, particularly the R-C circuit and C-R circuit analysis which it has been deployed for fixed bias circuit and then we will be moving to the common emitter amplifier with self-bias.

This part emphasizes the necessity to recapitulate the R-C and C-R circuits analyzed in earlier lessons as they are fundamental to understanding the new self-biased common emitter amplifier. Recapitulation strengthens knowledge and enables students to effectively transition to more complex concepts.

If you were building a house, you would revisit the blueprint (previous knowledge) before adding new structures. This ensures that the new changes are built upon a solid foundation, just like how the lessons are structured.

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