Design an opamp circuit with this transfer function on 3 voltage inputs

In summary, the conversation discusses building a circuit for a given operation on three voltages. The circuit uses a voltage summer and integrator to calculate the capacitance and resistance needed. The negative capacitance is caused by the signal being inverted by the op-amp based Miller integrator. It is also mentioned that the conversation is related to a homework assignment.
  • #1
DaniilMP3
2
0
TL;DR Summary: Build a circuit of given operation on voltages

I'll appreciate any help.
I need to create circuit of this operation on three voltages:
CodeCogsEqn (1).png

We'll use circuit of voltages summer:
Screenshot_2.png


The third term is the integral of U_3, so we'll use integrator:
Screenshot_3.png


Than, calculate capacitance:
CodeCogsEqn (4).png

And on this step we have negative capacitance. Is it possible? Or I did something wrong?
Next, we calculate R_1, R_2.
Screenshot_4.png

And here we have -44 kilo Ohm for R_2.
 
Physics news on Phys.org
  • #2
Welcome to PF.

Is this homework?

The negative sign comes from the simple op-amp based Miller integrator inverts the signal. If you want to cancel the negative sign, you will need to invert the signal in that branch, before or after the integration.
 
  • #3
Hi, yes. This is homework. Thank you for your response.
 
Last edited:
  • #4
DaniilMP3 said:
Hi, yes. This is homework.
(Thread moved to the schoolwork forums)
 

FAQ: Design an opamp circuit with this transfer function on 3 voltage inputs

What is the general approach to designing an op-amp circuit with a specific transfer function?

The general approach involves first understanding the desired transfer function and then selecting the appropriate op-amp configuration (e.g., inverting, non-inverting, summing, differential). Next, you calculate the necessary resistances and capacitances to achieve the required gain and phase characteristics. Finally, you assemble the circuit and test it to ensure it performs as expected.

How do I determine the resistances and capacitances needed for my transfer function?

To determine the resistances and capacitances, you need to break down the transfer function into its constituent parts (e.g., gain, frequency response). Use standard formulas for op-amp circuits such as the inverting and non-inverting amplifier equations, summing amplifier equations, and RC filter equations. These formulas will guide you in choosing the component values that satisfy the transfer function requirements.

Can I implement a transfer function with multiple voltage inputs using a single op-amp?

It depends on the complexity of the transfer function. Simple transfer functions with multiple inputs can often be implemented using a summing amplifier configuration with a single op-amp. However, more complex functions may require multiple op-amps in a cascaded or feedback configuration to achieve the desired performance.

What are the common pitfalls when designing op-amp circuits with specific transfer functions?

Common pitfalls include incorrect component values leading to the wrong gain or frequency response, instability due to improper feedback or loading, and overlooking the power supply requirements of the op-amp. It is also crucial to consider the bandwidth and slew rate limitations of the op-amp to ensure it can handle the desired signal frequencies without distortion.

How can I verify that my op-amp circuit meets the desired transfer function?

You can verify the performance of your op-amp circuit by simulating it using software tools like SPICE before physically assembling it. Once assembled, use an oscilloscope and a function generator to apply test signals and measure the output. Compare the measured output with the expected results based on the transfer function to ensure accuracy.

Similar threads

Time domain equation for RC circuit with AC input
Replies
4
Views
2K
How to determine drain-source voltage for this MOSFET amplifier.
Replies
0
Views
1K
Why does amplifier sink power for Vout>0 and sources power for Vout<0?
Replies
1
Views
1K
Engineering Circuit input impedance with ground in an OP Amp circuit
Replies
4
Views
2K
Solving Diff. Eqn & Designing Circuits: An Understanding
Replies
18
Views
2K
How Can an Op-Amp and Diode be Used to Convert 12V to 5V for a PIR Detector?
Replies
13
Views
2K
Transfer Function of a FET Differential Amplifier
Replies
4
Views
2K
From differential equations to transfer functions
Replies
5
Views
2K
Design Amplifier w/ 1k & 10k Resistors for +10 V/V Gain
Replies
4
Views
2K
Engineering How to Design a BJT Analog Circuit with Specific Transfer Characteristics?
Replies
3
Views
2K

Hot Threads

Recent Insights

Back
Top