# Calculate the transfer function of an OPAMP circuit

#### mmb1999

Mar 31, 2024
1
Hello All
I have an OPAMP circuit that its output increase steadily without cahnge in the input. I guess the issue is in the transfer function of the circuit and its stability. I want to calculate the transfer function of my circuit but I do not have any idea about that. Could you please help me to calculte the transfer function?

#### Attachments

• Screenshot 2024-03-31 180447.png
34 KB · Views: 11

#### Delta Prime

Jul 29, 2020
2,072
. I want to calculate the transfer function of my circuit but I do not have any idea about that.
You describe the circuit but you know what that circuit is called?
All the basic operational amplifier configurations.
But it's your job to know what type of operational amplifier it is...
The transfer function is simply an equation to derive the output of a specific type of operational amplifier.

#### Bluejets

Oct 5, 2014
7,009
without cahnge in the input
Are you sure about that as it would depend on the type of hall effect used.

Feb 19, 2021
787
Signal Flow Graph to get at T(s).

Or attached.

Your circuit will yield a 3'rd order T(s) as shown, not including the OpAmp internal
pole which would give a 4'th order equation. You can solve using node and Kirchoff,
which quite tedious, especially 3'rd order and above. Or one of the tools above.

Regards, Dana.

#### Attachments

• Signal Flow Graph 2 (1).zip
32.8 KB · Views: 6
Last edited:

Feb 19, 2021
787
I have an OPAMP circuit that its output increase steadily without cahnge in the input.

If input to an integrator is left unconnected it will integrate its own bias current,
so you will see a ramp, can be either + or - going ramp, until the output of the
integrator saturates, either close to + supply V or its - supply V.

Regards, Dana.

#### ramussons

Jun 10, 2014
467
Hello All
I have an OPAMP circuit that its output increase steadily without cahnge in the input. I guess the issue is in the transfer function of the circuit and its stability. I want to calculate the transfer function of my circuit but I do not have any idea about that. Could you please help me to calculte the transfer function?
What is the output from the Hall sensor? If the Quiescent output of the sensor is not Exactly 2.5 Volts (R1=R2), the output will linearly change to
0 or 5 volts, or
Sensor Quiescent * (R4/R5),
whichever is lower.

Replies
5
Views
880
Replies
11
Views
5K
Replies
19
Views
7K
Replies
7
Views
3K
Replies
2
Views
2K