91.3. Configuration 2: Current Sampling and Current Mixing

In this case we have changed both we have changed from voltage to current. So, what we said is that input as well as output both are current. So, here it is current and here also it is current. Of course, then this is unit less and you may say this is current gain. And likewise β is also unit less because it is converting current to current.

This chunk introduces the concept of Current Sampling and Current Mixing, explaining that in this configuration both the input and output signals are currents. It highlights the significance of the terms 'unitless' for both the current gain (A) and feedback factor (β), indicating that they represent the conversion of signal to the same type.

Think of this as a conversation over a walkie-talkie. You and your friend both speak in the same language (current), and anything you say is simply picked up and transmitted back without changing the form (unitless).

The sampler current sampler so, whatever the sampler we will be using at the output port it should be in series. So, if you see here, and if you recall the previous configuration there it was shunt connection; but in this case we do have output signal say i and this i need to be flowing through this path right. So, to have this current flowing through this input port. So, this port and this port they should be in series. So, the sampler these sampler it is actually series type of sampler.

In this chunk, the importance of the current sampler is discussed. The text explains that the sampler must be in a series configuration to allow the output current (i) to flow through the input port of the feedback network. This contrasts with previous configurations where a shunt connection was used.

Imagine a water pipe where the liquid must flow through one section (the sampler) before entering another section (the feedback network). If there’s a narrow path (series configuration), the water (current) can move freely through. If there were openings on the side (shunt), it wouldn't direct all the flow into the intended path.

On the other hand if you consider the input port. Since, we do have the feedback signal which is in the form of current and then primary signal it is also in the form of current; and if you want to mix two currents we have to make a parallel connection. So, the mixer it is a parallel mixer.

This chunk explains the current mixing configuration. It discusses how to mix currents and how the mixer operates in a parallel connection to combine the feedback current and primary signal current effectively.

Think of mixing different colors of paint. To get a new color, you would mix several colors together in a container (parallel connection). Just as the primary and feedback currents mix together to produce a new combined current output.

To avoid the loading effect, the situation here for the input; and output resistance of forward amplifier and the feedback path need to be appropriately changed. So, what we have here it is to avoid the loading effect here the input resistance it is 0. And the output conductance here it is 0 or output resistance is ∞.

In this chunk, the focus is on creating ideal conditions to avoid loading effects in the feedback system. It highlights the importance of setting the input resistance to zero and the output resistance to infinity to ensure accurate current sensing.

Consider this like having a perfectly smooth slide where there’s no friction (zero resistance) so that when you push something down, it moves freely without slowing down due to any obstructions (loading effects).

We call this is the +ve direction of the current; we call this is the +ve direction of the convention. And this is also +ve direction of the current. So, if I consider say this net and if I consider the KCL at that node, so we can easily see that i = i ‒ i.

This chunk highlights the importance of understanding the polarities of currents in the system. It describes how the current conservation law (KCL) applies, showing how the output relates to the input and feedback currents. The proper polarity of the signals ensures that the feedback is negative.

Think of a balance scale. If you add weight (current) on one side and take away from the other, knowing how much to add or remove keeps the scale from tipping (maintaining equilibrium). Understanding the direction of currents works similarly to ensure that feedback keeps the overall system stable.

As you can see that this current sampler it is if you see here it is a current sampler, and current mixer. Current sampler it is a series kind of connection, or series sampling. So, that the output current should be flowing through this input port of the on the feedback network.

This section explains how to name the different components of the system based on their configurations. It emphasizes the prefix 'current' to denote the type of signals and how the series and parallel configurations dictate the naming conventions.

Think of naming a recipe based on its ingredients and method. If a dish uses chicken and is fried, you’d likely call it 'Fried Chicken Dish' based on both key ingredients (current) and cooking method (series connection).

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