63.4. Coverage of Today's Lecture

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 problem we have said, and most likely we will be discussing on this BJT based on cascode amplifier.

In this lecture, we will focus on two main types of cascode amplifiers: one that utilizes Bipolar Junction Transistors (BJTs) and another that uses Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs). We have prepared detailed numerical problems that will allow us to explore these circuits practically, particularly emphasizing BJT-implemented cascode amplifiers.

Think of a cascode amplifier like a multi-story building. The lower floor (BJT) supports the rest of the building (the amplifier's overall function), while the upper floor (MOSFET) provides additional space and efficiency. Just as each floor has its own importance and function, each type of transistor contributes differently to the amplifier's performance.

And the MOSFET counterpart, what I mean is that similar kind of cascode amplifier can be constructed using MOSFET; and there also we do have very detailed numerical problem.

In addition to BJTs, we are also able to design a similar cascode amplifier using MOSFETs. This session will include specific numerical problems related to these cascode amplifiers, which help in reinforcing the theoretical knowledge through practical application.

Imagine engineers working with different materials to construct buildings; while one builds with bricks (BJT), another might use steel (MOSFET). Both have different properties but can achieve similar results, exemplifying how various components can work together in electronics to achieve effective outcomes.

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

Cascode amplifiers offer advantages over simple common-emitter (CE) amplifiers, primarily including improved bandwidth and stability. By stacking the transistors, the gain is maintained while reducing the loading effects on the preceding stage, leading to better overall performance over a wider frequency range.

Think of it like a relay race. If the first runner (CE amplifier) has to stop to hand over the baton, performance is affected. But with a well-coordinated team (cascode amplifier), the baton is passed seamlessly, maintaining speed and efficiency throughout the race.

But based on the time availability, I may be giving you some hint, but you have to work it out, ok.

While I can guide you through some examples, it's important for you to engage deeply with the numerical problems on your own. Solving these will reinforce your understanding of how cascode amplifiers operate, and how to calculate the necessary parameters.

Consider learning to ride a bike. Instruction helps you understand the steps, but until you actually try it yourself, you won't truly learn to balance and navigate. Similarly, working through these problems will help you gain practical experience and confidence in your skills.

--