Understanding Op Amp Offset Voltage: Rules & Examples

[ecestar]

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 .

 

[chroot]

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

 

[ecestar]

ok thanks

but can u give me any example with value of input and resistor and what the solution

 

[chroot]

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

 

[ecestar]

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

 

[chroot]

Can you show us a schematic?

- Warren

 

[ecestar]

who can i do that

 

[berkeman]

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.

 

[Bob S]

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

V_out = A{V₊ - V_- - V_offset]

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.

 

[ecestar]

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

 

[ecestar]

and i need example to show me the mean of offset please

 

[berkeman]

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.