Register to reply 
Integrating op amp questionby Cantstandit
Tags: integrating 
Share this thread: 
#1
Mar513, 03:18 PM

P: 30

Hello,
I'm having problem understanding the output of the integrating op amp. https://www.dropbox.com/s/djpg0uhi465ot86/download2.png https://www.dropbox.com/s/p9bp9tlyykhjtvf/download.png (hope you can see that, I can't see it on my preview) The blue line is input, orange is output. So if it's supposed to integrate, surely output signal has a wrong sign, doesn't it? If the integral is the area under the square signal, there should be linear increase when the signal is positive and linear decrease when it's negative, yet it's the other way around, why? I'd thought it was because my voltage had been applied to the inverting input of the opamp, but even when I flipped it, it stays the same... 


#2
Mar513, 07:03 PM

Sci Advisor
PF Gold
P: 3,657

Remember you have an inverting amplifier there.
The opamp will hold its inputs equal, and +input is at zero. Therefore whatever current is pushed into summing junction through R1 must get pulled back out through C1&R2,,,, ,,,so an input to output reversal of polarity is nessary. After the initial transient (power up i presume?) , output looks like it moves in right direction. http://www.ti.com/ww/en/bobpease/assets/AN31.pdf 


Register to reply 
Related Discussions  
Integrating factor question  Calculus & Beyond Homework  0  
ODE question  Integrating factor  Calculus & Beyond Homework  2  
Question regarding integrating (int(1/u))  Calculus & Beyond Homework  1  
Question integrating f(z)dz over a contour C  Calculus & Beyond Homework  4  
Quick integrating question...(part of a series question)  Calculus & Beyond Homework  3 