Understanding Op Amp Offset Voltage: Rules & Examples

  • Context: High School 
  • Thread starter Thread starter ecestar
  • Start date Start date
  • Tags Tags
    Amp Op amp Voltage
Click For Summary

Discussion Overview

The discussion centers around understanding operational amplifier (op-amp) offset voltage, including its definition, implications in circuits, and examples. Participants seek clarification on the concept and its practical applications, particularly in relation to specific components and configurations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related

Main Points Raised

  • Some participants describe offset voltage as the difference in voltage between the two inputs of an op-amp when it is expected to drive them to the same voltage.
  • One participant requests a practical example involving specific input values and resistors to illustrate the concept of offset voltage.
  • Another participant shares a scenario involving a temperature sensor and a voltage-controlled oscillator (VCO), noting the appearance of offset voltage in the results and expressing uncertainty about achieving the correct output.
  • There are suggestions for sharing a schematic to facilitate further discussion and troubleshooting of the circuit design.
  • A participant provides a formula for calculating output voltage in relation to offset voltage, indicating that in a voltage follower configuration, the output equals the offset voltage when the positive input is grounded.
  • Some participants suggest using online resources to find tutorials on op-amp offset voltage, indicating a reliance on external information for further understanding.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and seek different types of examples, indicating that there is no consensus on the best way to explain or demonstrate the concept of offset voltage. The discussion remains unresolved regarding specific examples and practical applications.

Contextual Notes

Some participants express difficulty in visualizing the circuit and suggest the need for a schematic, while others mention the limitations of older op-amps like the LM741 in relation to offset effects. There is also a mention of the need for specific examples to clarify the concept further.

ecestar
Messages
21
Reaction score
0
please

can anyone give me clearly information about Op Amp Offset Voltage

with simple example and rule to explain that becaus i was found diffecalt to understsnd it .
 
Physics news on Phys.org
An op-amp in a feedback circuit should drive its two inputs to the same voltage. In reality, the amplifier will have some error, and the two inputs will settle at slightly different voltages. The difference in the two voltages is called the "offset voltage" or "offset error."

- Warren
 
ok thanks

but can u give me any example with value of input and resistor and what the solution
 
I have no idea what you're asking for. If you need help with a homework problem, please show us the problem (exactly as it was given to you), show us your work, and explain how and why you're stuck.

- Warren
 
i want to send patient tempareture

so at first i have sensor (AD22100) with 10 degree range

after that send the voltage of the sensor to VCO to convert v/f (TS902).

but between the sensor and VCO i need op amp (741) but when i connect it the offset apper in the result and i am connect varaible resistor to the feedback of the op amp but i don't now how can i get the right result.

not: u can see the data sheet if u want about sensor (AD22100),VCO(TS9402).AMPLIFIRE (741).

THANKS
 
Can you show us a schematic?

- Warren
 
who can i do that
 
ecestar said:
who can i do that

How can you do that? If you have the schematic on your PC screen, you can press Alt-PrintScreen on most computers, and that will store a "screenshot" of the active window to the Windows Clipboard. Then go into an application like "Paint", and paste it in. Save it as a JPG file, or convert to PDF, and upload it here as an attachment (careful of the size -- there are limitations to upload file size). If the file is too big to upload, store it on an outside server or your own website, and post a link to it here.

Also, with an older non-CMOS opamp like the LM741, there is a trick to minimize input offset current effects (which can be worse than input offset voltage effects on some opamps). When you show us your schematic, we can look to see if you are using this trick correctly.
 
ecestar said:
please

can anyone give me clearly information about Op Amp Offset Voltage

with simple example and rule to explain that becaus i was found diffecalt to understsnd it .
For open loop

Vout = A{V+ - V- - Voffset]

If you build a voltage follower with gain of 1 (wire from Vout to V-), and ground the positive input, the output voltage is equal to the offset voltage.
 
Last edited:
  • #10
berkeman said:
How can you do that? If you have the schematic on your PC screen, you can press Alt-PrintScreen on most computers, and that will store a "screenshot" of the active window to the Windows Clipboard. Then go into an application like "Paint", and paste it in. Save it as a JPG file, or convert to PDF, and upload it here as an attachment (careful of the size -- there are limitations to upload file size). If the file is too big to upload, store it on an outside server or your own website, and post a link to it here.

Also, with an older non-CMOS opamp like the LM741, there is a trick to minimize input offset current effects (which can be worse than input offset voltage effects on some opamps). When you show us your schematic, we can look to see if you are using this trick correctly.


i don't software to draw this circut can u give me one
 
  • #11
and i need example to show me the mean of offset please
 
  • #12
ecestar said:
and i need example to show me the mean of offset please

Google is your friend. Learn to use it. I Googled the following (type it in the Google search box):

opamp input offset voltage tutorial

And Google came back asking if I meant:

op amp input offset voltage tutorial

to which I answered OK. Here is the hit list:

http://www.google.com/search?hl=en&...=op+amp+input+offset+voltage+tutorial&spell=1

There are many good hits, including a tutorial on your LM741 opamp (that's how I usually spell opamp, not op amp) as the first hit. Hope that helps.
 

Similar threads

Engineering Why is the voltage source high potential into node 1 at -12 V in this op amp problem?
  • · Replies 15 ·
Replies
15
Views
3K
Engineering What is the impact of ADC quanta on op-amp offset error?
  • · Replies 4 ·
Replies
4
Views
2K
Amplifier for piezoelectric sensor, OP Amp circuit
  • · Replies 6 ·
Replies
6
Views
6K
Engineering Op amp circuit -- Did I calculate the output voltage correctly?
  • · Replies 12 ·
Replies
12
Views
4K
Why does the amperage go real high if there is a low voltage short?
  • · Replies 17 ·
Replies
17
Views
2K
What's wrong in my LTspice simulation of an Op-Amp integrator circuit?
  • · Replies 9 ·
Replies
9
Views
8K
Engineering Calculating the unknown voltages in ideal op-amp circuits
  • · Replies 13 ·
Replies
13
Views
3K
Engineering Analyzing this operational amplifier circuit with DC
  • · Replies 8 ·
Replies
8
Views
2K
Calculating the voltage in an OP-amp circuit with a current source
  • · Replies 1 ·
Replies
1
Views
2K
Comparing Op-Amp Parameters: Ideal vs A & B
  • · Replies 3 ·
Replies
3
Views
2K