94.2.2. Final Remarks

So to summarize all these 4 sub-lectures, what we have discussed in this topic of feedback system. So far we have talked about basic concepts of the feedback system, there we have introduced how we define the feedback system and then we have talked about 2 basic types of feedback mechanism or feedback system namely, +ve feedback type and ‒ve feedback types feedback system.

In the introduction of feedback systems, we defined what a feedback system is and why it is essential in electronic circuits. We highlighted that there are two primary types of feedback: positive feedback, which amplifies the input signal, and negative feedback, which stabilizes the output by reducing gain. This foundational understanding serves as a basis for more complex discussions.

Think of a feedback system like adjusting the volume on a sound system. When the volume is too high and causes distortion (negative feedback), you turn it down for clarity. Conversely, if the sound is too low and you'd like to boost it (positive feedback), you turn it up. Feedback systems in electronics operate on similar principles.

And subsequent discussion it is mostly related to ‒ve feedback system. So then, we have talked about transfer characteristic of feedback system namely, feedback system transfer characteristic A = . So also, we have talked about loop gain = ‒ βA then, desensitivity factor, D = (1 + βA).

In discussing negative feedback, we emphasized the transfer characteristics of such systems. We defined the relationship where the overall gain (A) is determined by the loop gain (which is the product of feedback factor and amplifier gain, represented as -βA) and introduced the desensitivity factor (D) that quantifies how adverse effects on gain can be mitigated (D = 1 + βA). Understanding these terms is crucial for evaluating the performance and stability of feedback systems.

Imagine you're trying to balance a seesaw. If one side is heavier (think of this as applying a 'gain'), you'll need to add weight to the other side to level it out. The desensitivity factor can be thought of as a way to gauge how much weight you need to add to balance the seesaw, just like adjusting the feedback can stabilize the output in electronic systems.

Then we have talked about 4 basic configurations which normally it is common in electronic circuit and we have discussed about their characteristic. So these are the enlisted 4 basic configurations we have discussed about how the gain it is getting changed.

We discussed four common configurations of feedback systems used in electronic circuits: voltage series, voltage shunt, current series, and current shunt feedback. Each configuration has unique characteristics that affect how gain is modified, input and output resistances are altered, and the overall performance of the circuit is optimized. These configurations provide a framework for engineers when designing feedback systems to achieve desired performance.

Consider a water faucet with a varying flow of water. When you adjust the handle (like changing the feedback configuration), you either increase or decrease the water flow (gain). Similar to how different faucet settings can control water output, various feedback configurations allow engineers to control electrical signals.

And also we have talked about how the input resistance and output resistance of the system it is getting changed by the desensitization factor. And then we have discussed about 2 numerical examples associated with 2 feedback configure different types of configuration starting with ideal situation and then also we have moved to non-ideal situation.

In our discussion on practical applications of feedback systems, we analyzed how the input and output resistances are affected by feedback factors, illustrating the desensitization impact. We worked through two numerical examples that explored ideal and non-ideal feedback scenarios. By examining these calculations, students learned how theory translates into practical design challenges, enhancing their problem-solving skills.

Think about tuning a radio. In an ideal situation (like you can hear clearly), the signal is strong with minimal interference. But in a non-ideal situation (where there’s static), you need to adjust the dial (feedback) to minimize disturbances. The numerical examples provided are analogous to these tuning exercises, helping students see the practical application of theory in real-world scenarios.

--