I want to calculate capacitance from CV and I need to calculate integral of current as the question attached file. When I used integral from origin it have absolute area and mathematical area values.
I found some information from origin website (http://www.originlab.com/doc/Origin-Help/Math-Integrate) but I don know what Xo they used is O or the other value. Please tell me some advice what value is suitable for calculating capacitance?
The mathematical area is the area above the x Axis minus the area below the x Axis.
Hence the mathematical area of sin wave from x=0 to 2*Pi is zero because half of it is above the x axis and half of it is below the x axis. The absolute area though is twice the area above the x axis.
Now in your case. With the first graph you need to use a double integral as the left bound and the right bound is a curve, being careful as to whether you are above or below the origin
For the second graph you need to subtract the bottom curve from the top and displace both curves upwards so that the left intersection is on the x axis and not below it. The area between the two curves will then be positive and when you evaluate it you will get the absolute area.
for double integrals see
https://www.khanacademy.org/math/multivariable-calculus/double_triple_integrals/double_integrals/v/double-integral-1
Thank you so much for detailed answer. i will read it carefully.
Wish you have many lucky and success, bro :)
Have a look on the link
http://www.originlab.com/Index.aspx?go=Support/VideoTutorials&pid=2036
Thanks
Hello Tran Minh Hai.
For the second graph, easier way is just to reverse the X- and Y-axis from the plot setup. After that you can simply use the integrate function from Gadgets --> integrate.. to calculate the area for negative and positive current density.
Sincerely, Juho
Please see this video , it show the procedure for area calculation using origin software
How to calculate area under the curve in origin
https://www.youtube.com/watch?v=HwuvXcxz9fg
You have to be careful when using Absolute are vs Mathematical area. It depends where origin takes the baseline for integration. In my first image you can see a significant difference in the area when integrated using mathematical vs absolute. In the second picture I split the CV into two halves and used the Gadgets>Integrate tool too see what area was being calculated. I took the area below the top half of my CV curve and subtracted the area under the bottom half of the CV curve and it was equal to the Analysis>Integrate>Mathematical area. You can see in the pictures 238.9-1295= 109.4 which is very close to the 110.2 calculated using mathematical area.
I hope this helps
@ Jordan Milne: Thank you, Jordan. I used to try calculate Absolute and mathematical methods of CV curves and and compared them with values from charged/discharged time curves (symmetric triangle plot), then I realized that mathematical area of CV was more suitable than absolute value. It agrees with your answer. Thank you for showing me the clear explanation for this problem.
ahhh! its quite easy and the difference between the mathematical area and absolute area is very clearly presented in this link given below -
https://www.youtube.com/watch?v=FS3JxZmZnYY&list=UUwnKMOJn1CxTWWv1jUa0MSw&index=2
Minh-Hai Tran In this video, I have explained in details how to find area under the curve using origin. In the case you want to further ask about it, please do comment on the specific video, I'll respond to it shortly. I have provided the practice file(s) here. Thanks
https://youtu.be/DMsBzGCNHQk
What is the unit of absolute area ? That obtained from origin software.
I saw the video for calculating the specific capacitance. Cp. in F/g
the value of absolute Area obtained ( area under Curve CV) divided by 1000.
Then Used in eq; Cp = A/ 2 ( K *(v2-v1) * m )
So, I want to know the unit of area
Thank you
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