64.1. Analog Electronic Circuits

Welcome back after the short break. Before I going to the next topic I must see here that this calculation of the C I did a small mistake hear, it should be 135 because C = C + in π C (1 + 204) and so, here we do have 5 and also here we do have 10. So, I miss this 10 µ part. So, 10 + 1025. So, that gives us 1035 pF capacitance. So, it should be 1035, this calculation remains the same ok.

In this chunk, the speaker acknowledges a mistake made in a previous calculation regarding capacitance. The correct formula is provided, which indicates that capacitance C can be derived as C plus a term involving C in and π. The final calculation yields a capacitance of 1035 picofarads (pF). This is an illustration of the importance of precision in electrical calculations, where a small error can lead to significant differences in results.

Consider a chef measuring ingredients for a recipe. If the chef mistakenly forgets to include a critical ingredient or measures it inaccurately, the final dish could taste entirely different. Similarly, precise calculations are crucial in electronics design, where each component must be accurately accounted for.

So, far what we have discussed that the advantage of cascode amplifier with respect to standard CE amplifier and namely what you have seen is that in case if you are retaining this passive element for both the cases, then gain wise we do not get much advantage. But then what we have seen that in case if we have the input resistance and the source resistance together forming a significant significantly low frequency pole due to this large value of the C , in then we have seen that the cascode amplifier it is giving some advantage.

This section highlights the advantages of using a cascode amplifier compared to a standard common-emitter (CE) amplifier. While keeping passive components the same does not significantly enhance gain, the cascode design improves performance at particular frequencies by helping avoid significant low-frequency issues that arise due to input and source resistances coupled with large capacitor values. Essentially, the cascode structure leads to a better frequency response.

Think of a highway system where an exit ramp is unexpectedly closed. Standard routes quickly become congested. However, a newly designed dual-lane expressway (similar to a cascode amplifier) can direct traffic around the congestion more effectively, allowing for smoother travel even when there is a lot of other traffic.

Now it may be a situation where this resistance it may be small or whatever the cutoff frequency we are obtaining by this R and then C and R that may be beyond the upper cutoff frequency defined by R and the C . So, far such case you may say that then what is the advantage of cascode amplifier. In fact, cascode amplifier it is having two types of advantages; one is extending the bandwidth as we just now we have discussed particularly in presents of significantly large value of the source resistance, the other advantage which is commonly used is that the increasing the gain drastically.

In this passage, the speaker introduces the idea that the cascode amplifier can extend bandwidth significantly, especially when a large source resistance is present. Additionally, it is mentioned that these amplifiers can drastically increase the gain, allowing circuits to perform better under various conditions. This highlights the flexibility and utility of cascode amplifiers in electronics.

Imagine a concert hall where sound can be amplified through a system of speakers. If the main speakers struggle to project sound due to crowd noise (representing low bandwidth), adding additional speakers in strategic locations (the cascode amplifier) allows for better sound distribution across a larger area, overcoming initial limitations and enhancing the overall experience.

So, to demonstrate the capability of the cascode amplifier to increase the gain first of all let we consider a different situation instead of having this R if you put some active circuit there, probably then the advantage of the cascode amplifier particularly for enhancing the gain it will be quite prominent.

Here, the speaker suggests evaluating a scenario where an active circuit replaces a passive one, thereby allowing the advantages of the cascode amplifier to be more effectively demonstrated. The discussion implies that the interplay of resistances and active circuit designs can massively influence gain and performance in practical applications.

Consider building a bridge over a river. Using simple planks (passive components) might allow limited passage. However, employing a more sophisticated suspension design (active components) can enable more vehicles to cross safely and efficiently, enhancing traffic flow and access significantly.

--