99.6.1. Component Values and Calculations

So, the main circuit it is given here and the along with this we do have an intention to get G trans-conductance of the circuit defined by feedback network. So, if I consider this m G , if we see the G in this summary table of feedback effect, what we can see here it is m suggests that we need to have current-series feedback or series-series feedback. And for series-series feedback, what we have the input signal, it is voltage and the output signal it is current.

In this section, we begin by describing the feedback circuit in terms of its trans-conductance (G) and the necessary conditions for achieving series-series feedback. This type of feedback requires a voltage input signal and a current output signal. The section sets up the foundation for understanding how feedback affects the circuit's performance.

Imagine a water pump (which represents our circuit) that needs feedback to operate efficiently. The more water it pumps out (current), the more effort it needs to maintain the right pressure (voltage). By adjusting the feedback mechanism, we ensure that the pump operates steadily without overloading.

So, we can say that input signal it is voltage and then output signal it is current and then forward amplifier gain it is trans-conductance amplifier. So, I should say A = G and the transfer function of the feedback network β which converts the output signal into input signal of voltage which means that it is unit it is Ω.

Here, we define the relationship between input and output signals in the context of our circuit. The circuit's forward gain (A) is essentially equal to its trans-conductance (G), linking the output current back as a voltage input through a feedback network represented by β. The significance of the unit Ω indicates the resistance encountered by the feedback mechanism.

Think of a thermostat in your home. The thermostat receives a temperature input (voltage) and adjusts the heating system based on how much heat is actually being produced (current). The thermostat's setting (gain) adjusts the heating until the desired temperature is achieved.

So, here also from the table we can see that unit of the feedback network it is Ω and what we can say that while we are making this circuit, it is anticipated that the input resistance it will increase and also the output resistance it will increase.

The feedback network's resistance is crucial as it impacts both input and output resistance. By applying feedback, we increase the input resistance, allowing the circuit to draw less current, while the output resistance increases, affecting how the circuit interacts with subsequent stages or loads.

Consider water flowing through a narrow pipe. When you increase the diameter of the pipe (feedback), the flow rate can still be controlled while allowing more water to move through without losing pressure. This illustrates how feedback can change the 'resistance' faced by the circuit.

Now, while we will be observing the output, output it is as I said that it is in the form of current. So, to get a current here what we can say it is we can connect a capacitor to ground and then we can see how much the current it is flowing through this circuit which I referred as i .

This part focuses on how to measure the output current using a capacitor connected to ground. The current flowing through the circuit is observed and designated as 'i', helping to indicate how the feedback network modifies performance by sampling the output.

Imagine a teacher using a microphone. The microphone captures the teacher's voice (current) and sends it to speakers (feedback), spreading the sound throughout a classroom. Here, the capacitor serves as a medium to capture and transmit the current effectively.

So, if you look into this model given here, the developed voltage which is equal to the output current. In fact, i it is same as i while it is flowing through this feedback network it is developing a voltage here and that voltage need to be mixed here.

As we analyze the feedback circuit, the output current is directly linked to the developed voltage, which then gets mixed back into the circuit. This highlights how outputs feed into the feedback mechanism to stabilize and enhance performance.

Think about how a musician might adjust their singing based on the sound they're hearing from the audience's response. The feedback from the audience (output current) helps the musician refine their performance (developed voltage).

--