45.4.2. Behavior Remains Unchanged

Now, if I consider say source resistance and still if I consider this is 0 then even if I connect the source resistance R , since from this terminal to this terminal, there is no DC path. So, you may say that even if I consider R the behavior of the circuit remains unchanged.

In this part, we are discussing how the introduction of a source resistance (R) does not impact the behavior of the circuit when connected to a specific terminal. It is asserted that there is no direct DC connection between the aforementioned terminals, thus, the overall functionality and response of the circuit remain intact regardless of the presence of this resistance.

Imagine trying to pour water through a pipe with a blockage halfway down; if that part of the pipe (like the source resistance) does not impact the water flow at the opening (the circuit behavior), you can say the water will still flow as if the blockage doesn’t exist - the overall system behaves as intended.

However, if I consider say common collector stage; obviously, there will be the corresponding element here called r . So, it is better to in case if we consider R , then we need to; need to analyze its effect particularly for common collector stage.

In contrast to the previous general case, this section emphasizes the necessity of evaluating circuit behavior in the presence of a source resistance when dealing with a common collector stage. The text indicates that this stage comes with its own intrinsic resistance, namely 'r', which requires careful consideration to understand how it behaves when the source resistance is present.

Think of the common collector stage like a food delivery service. While traffic (the source resistance) might not impede overall service delivery in a clear route, introducing an additional unexpected detour (like the resistance 'r') can change how long it takes for food to arrive, thus requiring a reevaluation of the delivery times.

So, let us see the common collector amplifier considering this source resistance, signal source resistance. So, we do have the circuit given here. So, we are considering this source resistance R . Again, R we are ignoring, so we are considering one effect at a time.

In this section, the focus shifts to assessing the actual effects of the source resistance on the common collector amplifier. The process begins with visualization of the circuit and noting that only one aspect, the source resistance (R), is analyzed while temporarily ignoring other factors ('R'). This step-by-step approach helps simplify complexities in understanding how the source resistance could affect the circuit characteristics.

Consider a race where runners are allowed to wear only one type of shoe at a time to compare their performance. Similarly, by fixing on source resistance 'R' while ignoring potential complications from other resistances, we can better evaluate its specific impacts on the common collector amplifier's performance, just like running in one shoe helps isolate its effect on speed.

So, if I multiply this with v that gives us the base voltage, and then from the base point to the corresponding collector point the gain it is approximately 1.

This part explains how the voltage gain is affected by the source resistance. When considering the relationship between the input voltage and the output (base voltage) after accounting for the source resistance, the overall gain remains close to one. This indicates that the amplifier allows any signal level to pass through effectively without significant attenuation.

Imagine a sound system where adjusting the equalizer doesn’t significantly change the sounds from speakers. If you turn the dial for bass or treble very slightly but get the same loudness and clarity, that's akin to our condition here: the voltage gain adjusts but retains the same effective output, thus behaving 'approximately' consistently as before.

To get the source resistance sorry the output resistance of this circuit, what you have to do? We need to stimulate the circuit by say v and we need to observe the corresponding current here i.

In this section, the steps for determining the output resistance in the presence of source resistance are described. It involves applying a voltage to stimulate the circuit and measuring the resulting current. This observation will help draw conclusions about how the output resistance behaves when influenced by the source resistance.

Just like testing the flow rate of water from a hose when adjusting the nozzle to see how much pressure changes the flow, similarly, applying voltage here helps unveil how current flows and what resistance levels alter its behavior across the circuit.

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