Loading the lesson
Loading the lesson
Search AllRounder.ai
Search the courses, subjects, tracks, games and features, or jump straight to a page.
Search the courses, subjects, tracks, games and features, or jump straight to a page.
Learn it your way
A short class with Sarah and her students. The other ways are under More.
Sign up free to listen. Transcripts are free to read.
Today we'll calculate the voltage gain of our feedback system using the formula for voltage gain, A = Af / (1 + βAf), where Af is the forward amplifier gain and β is the feedback factor.
So, for our example with Af being 200 and β being 0.095, what will our gain be?
Good question! First, we can substitute these values into the formula. Let's compute it together.
Isn't the desensitization factor also involved in this calculation?
Correct! The desensitization factor is important as it affects our gain and input/output resistances. Remember: the higher the gain of the forward amplifier, the more influence it has on the feedback system.
Can we summarize the steps involved in calculating the voltage gain?
Absolutely! Step one: identify your Af and β. Step two: plug into the formula. Step three: calculate and interpret the result. Remember to keep track of the units!
Now let's move on to input resistance. We know from our earlier calculation of feedback that input resistance can be affected by feedback. Can anyone tell me how?
The input resistance increases due to the desensitization factor!
Exactly! The formula is Rin = Rn * (1 + βAf). Why do you think this is useful in circuit design?
It allows us to tailor the input resistance to align with specific circuit needs!
Exactly right! And the same concept applies when calculating output resistance, which often decreases due to feedback. Let's calculate it!
So if we have output resistance R0 and we apply feedback, what does the formula look like?
The output resistance when feedback is applied becomes R0'/ (1 + βAf). Remember, feedback can increase our input resistance while reducing our output resistance.
Now that we understand voltage gain and how it affects input and output resistances, let’s move to output voltage calculation. Who can tell me how to derive the output voltage?
Based on the input voltage multiplied by the gain!
Exactly! If our input voltage is 100 mV and our gain from earlier was calculated at 10, what would that make our output voltage?
That would be 10 times 100 mV, which is 1 V!
Good job. It's all about understanding how each component works in relation to one another. Keep these formulas handy as they'll help you in circuit analysis!
Can you recap the key points we need to remember for output voltage?
Sure! Remember: identify input voltage, compute voltage gain, and multiply. Always check back with our formulas!
Now let’s consider non-ideal feedback. How do we need to adjust our calculations from the ideal case?
We have to account for finite input and output resistances and possibly apply additional equations.
Right! Can anyone remember what the loading effect does in our calculations?
It changes the effective gain by factoring in the load connected to the circuit!
Correct! And for our next example, we will compute both loading factors and their effects on our voltage output and other parameters.
Can you show us how the formulas will change in this case?
Certainly! We’ll adapt our previous formulas to include these new parameters, so be ready to recalculate everything!
Presents the importance of calculating performance metrics in the context of a feedback system.
Discusses the scenario with an ideal feedback network vs one with finite resistances, emphasizing how these conditions affect system parameters.
Derivations and explanations of the associated mathematical formulas to compute values such as input and output resistances and voltage gains.
Explains how feedback impacts input and output resistances and how they can be adjusted through feedback configurations.
Each calculation illustrates essential principles within electronic circuits, offering insights into design considerations for effective feedback amplifiers.
In Case 1, the voltage gain of the feedback system was calculated to be 10 using the given forward amplifier gain of 200 and the feedback factor of 0.095.
In Case 2, the introduction of finite input and output resistances reduced the voltage gain and adjusted the input and output resistances accordingly.
Gain of voltage is your game, feedback factor holds the fame!
Imagine a party where everyone is invited (feedback) ensuring no one arrives late (input/output conditions) improving the overall experience (performance).
FOR VGiN - Forward for Output, Resistances, Voltage Gain & Input Needs.
RIG - Remember Input Gain for feedback analysis.
Term
Voltage Gain
Click to flip
Term
Feedback Factor (β)
Click to flip
Term
Desensitization Factor
Click to flip
The ratio of output voltage to input voltage, typically expressed in decibels (dB).
A measure of how much of the output is fed back into the system input.
The factor that quantifies the extent to which feedback affects the input and output resistances of a feedback system.
The resistance seen by the input signal when applied to the amplifier, which can change due to feedback.
The resistance seen at the output of the amplifier, often decreased by feedback.
This section discusses the calculations necessary to analyze a feedback system, including input and output resistances, voltage gain, and output voltage.
In this section, numerical examples are presented to illustrate how to determine the voltage gain, input resistance, output resistance, and output voltage of a feedback system. It highlights both ideal and non-ideal conditions, showcasing the impact of different parameters on the feedback system's performance.
This section delves into the analysis of a feedback system for analog electronic circuits, focusing on calculating important performance metrics such as voltage gain, input resistance, output resistance, and output voltage in response to a given input signal. The analysis is guided by specific parameters including input and output resistances of the forward amplifier, its gain, and the feedback factor.
Each calculation illustrates essential principles within electronic circuits, offering insights into design considerations for effective feedback amplifiers.