Analyze this opamp active filter circuit

In summary, the conversation is about trying to solve a circuit problem involving an IdeaI OPAMP and finding the function Vs/Ve. The speaker has tried to simplify the problem by not summing up any components and has arrived at equations for E, S, and the desired function E=f(i2). However, they are unsure if their final result is correct. The other speaker suggests solving the problem using the Kirchhoff Current Law (KCL) equations and asks for the equations to be shown. They also mention the possibility of solving with phasors or differential equations and suggest checking the answer by doing it both ways. The first speaker agrees to try both methods and shares their final result, mentioning a correction for the equation.
  • #1
ace130
8
0
Hello, so this the circuit of an IdeaI OPAMP.
R7Umlxl.jpg

The Question is to find the function Vs/Ve .
I tried to make some sum ups to simplify it but I still unable to find a solution, so I tried to NOT sum up any component and found this:
E-S=iZ+i2(Z+R)
E=iZ+i3R
S=i2R
so the idea is to find E=f(i2) , This is the final Result but I'm not sure if it's correct :
50QjLNT.jpg
 

Attachments

  • R7Umlxl.jpg
    R7Umlxl.jpg
    7 KB · Views: 862
  • 50QjLNT.jpg
    50QjLNT.jpg
    11.1 KB · Views: 783
Last edited by a moderator:
Physics news on Phys.org
  • #2
ace130 said:
Hello, so this the circuit of an IdeaI OPAMP.
View attachment 219618
The Question is to find the function Vs/Ve .
I tried to make some sum ups to simplify it but I still unable to find a solution, so I tried to NOT sum up any component and found this:
E-S=iZ+i2(Z+R)
E=iZ+i3R
S=i2R
so the idea is to find E=f(i2) , This is the final Result but I'm not sure if it's correct :
View attachment 219619
I'm not quite sure what you are doing with your equations, but are you familiar with how to solve circuit problems using the Kirchhoff Current Law (KCL) equations? I would write the KCL equations for the two nodes in the middle (the - input of the opamp and the middle connection point between the 3 capacitors), and solve those simultaneous equations for the gain of the circuit s(t)/e(t).

Also, are you supposed to be solving this with phasors or differential equations?
 
  • #3
Yes i know the KCL , also this should be solved in complex .
I don't know if I should sum up those Rs and Cs or just write KCL that will take more time
 
  • #4
ace130 said:
Yes i know the KCL , also this should be solved in complex .
I don't know if I should sum up those Rs and Cs or just write KCL that will take more time
I don't know of a technique to "sum up" the Rs and Cs, but there may be one. Why not do it both ways to check your answer?

Can you show us the two KCL equations that I mentioned? Then show how you would solve them simultaneously...
 
  • #5
this is the KCL and loops
frLP0ia.jpg


and this is the final result:
50Ri9vs.jpg

Edit : the final line it should be Zc not 1/Zc .
 

Attachments

  • frLP0ia.jpg
    frLP0ia.jpg
    29.6 KB · Views: 267
  • 50Ri9vs.jpg
    50Ri9vs.jpg
    28.9 KB · Views: 263
  • #6
Your equation (2) is not right. It suffers from a sign convention error.
 

1. What is an opamp active filter circuit?

An opamp active filter circuit is a type of electronic circuit that uses operational amplifiers (opamps) to filter out certain frequencies from a signal. It is commonly used in audio and signal processing applications to remove unwanted noise or amplify specific frequencies.

2. How does an opamp active filter circuit work?

The opamp active filter circuit works by using the opamp's amplification and feedback properties. The input signal is fed into the opamp, which amplifies it and sends it to the output. The output signal is then fed back into the input through a feedback network, which adjusts the amplification and filters out certain frequencies based on the components used.

3. What are the advantages of using an opamp active filter circuit?

One advantage of using an opamp active filter circuit is that it can provide high levels of amplification and filtering while using a smaller number of components compared to passive filters. It also allows for greater control over the filter's characteristics, such as cutoff frequency and slope.

4. What are the key components of an opamp active filter circuit?

The key components of an opamp active filter circuit include the opamp itself, resistors, capacitors, and sometimes inductors. The opamp serves as the main amplification element, while the resistors and capacitors form the feedback network and determine the filter's characteristics.

5. How do I analyze the performance of an opamp active filter circuit?

The performance of an opamp active filter circuit can be analyzed by looking at its frequency response, which shows how the filter affects different frequencies of the input signal. The gain, bandwidth, and cutoff frequency can also be calculated using the circuit's components and the opamp's specifications.

Similar threads

Finding R and C values for an active second-order bandpass filter
    • Engineering and Comp Sci Homework Help
Replies
16
Views
2K
What is the potential at the top of R2 in this circuit?
    • Introductory Physics Homework Help
Replies
16
Views
3K
Finding currents in branches of a circuit
    • Introductory Physics Homework Help
Replies
1
Views
4K
Engineering Is it possible for a low pass filter to have such a transfer function?
    • Engineering and Comp Sci Homework Help
Replies
16
Views
962
Engineering Why are the voltages calculated in this way? (CE BJT Amp circuit)
    • Engineering and Comp Sci Homework Help
Replies
8
Views
1K
What is the correct way to analyze a circuit with resistors?
    • Introductory Physics Homework Help
Replies
8
Views
2K
Find S/E in Filtres & OPAMP Circuits: A Complex Schema
    • Advanced Physics Homework Help
Replies
6
Views
925
Finding Vout/Vin of an RL filter
    • Introductory Physics Homework Help
Replies
9
Views
6K
Effect of different magnetic fields on a magnetic dipole
    • Introductory Physics Homework Help
Replies
25
Views
279
Analyzing a Circuit with Phasors: Determining Inductance and Resistance
    • Introductory Physics Homework Help
Replies
8
Views
2K

Hot Threads

Recent Insights

Back
Top