Professional Courses
Industry-relevant training in Business, Technology, and Design to help professionals and graduates upskill for real-world careers.
Categories
Interactive Games
Fun, engaging games to boost memory, math fluency, typing speed, and English skillsβperfect for learners of all ages.
Typing
Memory
Math
English Adventures
Knowledge
Interactive Audio Lesson
Listen to a student-teacher conversation explaining the topic in a relatable way.
Current Gain
Unlock Audio Lesson
Signup and Enroll to the course for listening the Audio Lesson
Today, we're discussing current gain in amplifier circuits. Can anyone tell me what current gain refers to?
Isn't it the ratio of output current to input current?
Exactly! It's commonly denoted as A. When feedback is applied, do you think this current gain changes?
I wonder if it stays the same because feedback is supposed to stabilize things.
You're right! The current gain remains unchanged due to the balancing effects of feedback. Remember this: 'Feedback boosts stability, holding gains in equilibrium.'
Why is it important that the current gain doesn't change?
Great question! It allows designers to predict performance without unexpected alterations when feedback is introduced. Let's summarize: Current gain remains constant due to feedback's stabilizing effect.
Voltage Gain
Unlock Audio Lesson
Signup and Enroll to the course for listening the Audio Lesson
Now, let's shift our focus to voltage gain. Can anyone recall how feedback influences voltage gain?
From what we learned, the gain decreases with feedback, right?
Correct! However, as the voltage gain decreases, the output resistance increases simultaneously. Can anyone explain why this happens?
Because feedback essentially redistributes the signal effects throughout the circuit?
That's a great observation! The increased output resistance counteracts the decreased gain, keeping voltage gain stable overall. Let's cement this concept with a mnemonic: 'Vicious Velcro β Voltage remains, though resistance gains.'
That helps a lot! So, we won't see any change in voltage gain even with feedback?
Exactly! Due to the balancing nature of these characteristics, voltage gain retains its value. Let's recap: Voltage gain is stable due to simultaneous decreases and increases.
Trans-Impedance
Unlock Audio Lesson
Signup and Enroll to the course for listening the Audio Lesson
Finally, letβs investigate trans-impedance. What does trans-impedance represent in our circuits?
Is it the output voltage per input current?
Yes, thatβs right! Trans-impedance is defined as Z = V/I. Now, how does feedback affect this parameter?
I think it increases because feedback enhances overall stability and performance?
Indeed! The output voltage rises more than the input current response diminishes, resulting in increased trans-impedance. As a mnemonic: 'Zig-Zagging in circuits, trans-impedance escalates.'
That makes sense! So, trans-impedance benefits from feedback, unlike voltage and current gains.
Exactly! It's crucial to distinguish these differences. In summary: Trans-impedance increases due to effective feedback in the circuit.
Introduction & Overview
Read a summary of the section's main ideas. Choose from Basic, Medium, or Detailed.
Quick Overview
Standard
The impact of feedback on amplifier circuits is examined, focusing on how both voltage and current gains decrease while input and output resistances increase. The section also explains the significance of trans-impedance and provides guidelines for selecting feedback values.
Detailed
Changes in Voltage Gain and Current Gain
In this section, we explore the effects of feedback on voltage gain, current gain, and trans-impedance in analog circuits. Feedback is an essential technique employed in amplifiers to enhance stability and performance. Feedback affects the gains and resistances as follows:
- Current Gain: The current gain, denoted as A, is found to remain unchanged despite the introduction of feedback. This is attributed to the relationship between the current gain (G) and the load resistance (R), where both parameters are influenced similarly by feedback.
- Voltage Gain: The voltage gain also remains constant due to the opposite effects on the gain (G) decreasing and resistance (R) increasing by the same factor. Therefore, any change in one is countered by a change in the other, illustrating the principle of feedback stability.
- Trans-Impedance (Z): In contrast to the gains, trans-impedance increases due to similar overlapping effects of reductions and increases in the circuitβs transconductance and resistances. This effect is crucial in applications necessitating high degrees of precision.
Feedback configurations significantly influence circuit characteristics. The adjustments necessitated in selecting resistance values ensure that the amplifier operates efficiently and effectively. Understanding these dynamics is vital for any engineer or technician working with analog circuits.
Youtube Videos
Audio Book
Dive deep into the subject with an immersive audiobook experience.
Desensitization Factor
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
In fact, we are making this G getting reduced by a factor of that desensitization. So, this is getting decreased D = (1 + Gβ² Ξ² ) and it is (1 + g R).
Detailed Explanation
The desensitization factor is a key metric in feedback circuits. When feedback is applied to an amplifier, it can reduce the gain, denoted by G and Gβ². The desensitization factor D reflects this reduction and is calculated as D = (1 + Gβ² Ξ²) or D = (1 + g R), indicating how much the gain has decreased due to the feedback mechanism.
Examples & Analogies
Think of a speaker with a loud sound system. When you adjust the volume down to avoid distortion, you are effectively desensitizing the output sound level. Similarly, feedback in circuits lowers the overall gain to prevent distortion in signals.
Changes in Input and Output Resistance
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
Also, we know that input resistance getting increased by this factor, output resistance it is also getting increased by the same factor D.
Detailed Explanation
When feedback is applied, both the input and output resistances of the amplifier circuit increase by the same desensitization factor. This change is significant because a higher input resistance can improve the circuit's ability to not load the source signal too much, while a higher output resistance may be advantageous in certain applications.
Examples & Analogies
Imagine you have a sponge (input resistance) and you are trying to absorb water (input signal). If the sponge increases in size (input resistance increases), it can hold more water without becoming too saturated, thereby preventing interference with your work.
Current Gain
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
If I want to see what kind of changes do you expect or do you see for a current gain, then, we have to look into the expression of the current gain in terms of G. A = G R.
Detailed Explanation
Current gain in an amplifier circuit is defined by the relationship A = G R, where G is the trans-conductance and R is the resistance in the circuit. It can be observed that although G decreases due to feedback, R increases correspondingly, resulting in no change in the overall current gain.
Examples & Analogies
Consider a water pump that can push water (current) through a pipe. If the capacity of the pump decreases (lower G) but the pipe diameter increases (higher R), the overall flow rate remains the same. This mirrors how feedback affects current gain in amplifiers.
Voltage Gain
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
If I consider the expression of the voltage gain from here which is G m times R. A = G R and here again G it is decreased but R it got increased by the same factor D.
Detailed Explanation
Voltage gain is described by the expression A = G R. Even if G decreases due to feedback, the resistance R increases by a correspondingly matching factor. As such, the changes in G and R counteract each other, leading to no observable change in voltage gain.
Examples & Analogies
Picture a seesaw at the playground: if one side is lowered (reduced gain), the other side can be lifted (increased resistance), thereby keeping the seesaw level (no change in voltage gain). This image helps visualize how opposing changes in circuit parameters balance out.
Trans-impedance
Unlock Audio Book
Signup and Enroll to the course for listening the Audio Book
If I consider Z and its expression can be obtained from this column; namely, it is G, so Z = trans-impedance = G R R. And due to the feedback connection G got decreased R got increased.
Detailed Explanation
Trans-impedance is a crucial parameter defined as Z = G R R. Under feedback conditions, while G decreases, both R and R increase. The combined effect is that the trans-impedance increases, showcasing how feedback can enhance certain attributes of a circuit.
Examples & Analogies
Imagine a funnel that helps direct water flow (trans-impedance). If the input flow decreases (G decreases) but the funnel's neck widens (R increases), more water directed efficiently can lead to a greater output flow overall, mirroring the increase in trans-impedance.
Definitions & Key Concepts
Learn essential terms and foundational ideas that form the basis of the topic.
Key Concepts
-
Feedback: A technique that applies part of the output back to the input for improved control.
-
Current Gain: Remains constant despite feedback application due to balancing factors.
-
Voltage Gain: Stays constant because of reciprocal effects of feedback on output resistance.
-
Trans-Impedance: Increases under feedback, representing enhanced stability in an amplifier.
Examples & Real-Life Applications
See how the concepts apply in real-world scenarios to understand their practical implications.
Examples
-
In an amplifier circuit, feedback is used to stabilize currents, ensuring consistent operation.
-
Trans-impedance increases proportionally with effective feedback implementation, enhancing signal strength.
Memory Aids
Use mnemonics, acronyms, or visual cues to help remember key information more easily.
π΅ Rhymes Time
-
Feedback stabilizes, no gain surprise; current, voltage hold tight, resistances increase in flight.
π Fascinating Stories
-
Imagine an amplifier on a tightrope. When feedback is applied, it balances perfectly, keeping its current steady as it walks, with voltage and resistance adjusting just so.
π§ Other Memory Gems
-
C-V-T: Current gains stay steady, Voltage does too, Trans-impedance for breakthroughs.
π― Super Acronyms
CUT
- Current Unaffected
- Voltage Constant
- Trans-Impedance Rising.
Flash Cards
Review key concepts with flashcards.
Glossary of Terms
Review the Definitions for terms.
-
Term: Voltage Gain
Definition:
The ratio of the output voltage to the input voltage in an amplifier circuit.
-
Term: Current Gain
Definition:
The ratio of the output current to the input current in an amplifier circuit.
-
Term: TransImpedance
Definition:
A measure of the output voltage in relation to the input current in an amplifier, defined as Z = V/I.
-
Term: Feedback
Definition:
A process in which a portion of the output signal is fed back into the input to enhance system stability and control.
-
Term: Desensitization Factor
Definition:
A factor that describes how feedback affects the input and output resistances of a circuit.