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AC sources

Posted Dec 15, 2012, 7:39 a.m. EST Low-Frequency Electromagnetics, RF & Microwave Engineering, Heat Transfer & Phase Change, Parameters, Variables, & Functions Version 4.2a, Version 4.3a 6 Replies

Amr Abdelghany
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Hi All,

I am working on a project using comsol and I need to define an AC source. I want to use the Ac source to see the effect of bioheating. I don't know how to define an AC source and how to use it?.

Could any body help me how to define a new AC source and how to use it with the bioheating interface?


Thanks in advance

Amr
6 Replies Last Post Dec 17, 2012, 3:25 a.m. EST
Edgar Kaiser
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Posted: 1 decade ago Dec 15, 2012, 7:50 a.m. EST
Hi,

a search on the forum using the term 'AC source' gives you hundreds of hits. Give it a try.

Cheers
Edgar
Hi, a search on the forum using the term 'AC source' gives you hundreds of hits. Give it a try. Cheers Edgar
Amr Abdelghany
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Posted: 1 decade ago Dec 15, 2012, 8:19 a.m. EST
Hi Edgar,

I have searched the forum before the post,but I found that most post don't answer my question so I decided to post it.
Most posts on the forum are related to frequency domain study which is by default introduce harmonics to the sources,i.e frequency domain study implicitly define an AC source, But my question is about stationary study . I hope you could help me with this issue.

Thanks for your reply,

Amr
Hi Edgar, I have searched the forum before the post,but I found that most post don't answer my question so I decided to post it. Most posts on the forum are related to frequency domain study which is by default introduce harmonics to the sources,i.e frequency domain study implicitly define an AC source, But my question is about stationary study . I hope you could help me with this issue. Thanks for your reply, Amr
Amr Abdelghany
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Posted: 1 decade ago Dec 15, 2012, 8:47 a.m. EST
I have found that I can use waveform function to generate an AC current (for example)...is it valid or true?

Thanks again,

Amr
I have found that I can use waveform function to generate an AC current (for example)...is it valid or true? Thanks again, Amr
Fazlul Rahman Mohd Yunus
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Posted: 1 decade ago Dec 17, 2012, 12:26 a.m. EST
Hi Edgar,

I am using electrical current(ec) and electrical circuit (cir) to analyse potential distribution in a cylindrical cell (100mm) with water as medium. I applied sinusoidal current of 1mA 100kHz to excitation aluminum electrode (terminal1) and the other electrode as sink electrode which is connected to resistor and then to the ground. I have to use ext I vs U which is connected to the resistor, if not error occur during simulation. After simulation I found that the surface potential closed to the excitation electrode is 697.12V while the potential at the sink electrode is 4.93e-4. I am expecting that the potential close to the excitation should be around a few volts. What went wrong here? Another thing is why I need to use ext I vs U in the connection? I had referred to the manual and could not understand. Please advice. Thank you in advanced.

Regards
Fazlul
Hi Edgar, I am using electrical current(ec) and electrical circuit (cir) to analyse potential distribution in a cylindrical cell (100mm) with water as medium. I applied sinusoidal current of 1mA 100kHz to excitation aluminum electrode (terminal1) and the other electrode as sink electrode which is connected to resistor and then to the ground. I have to use ext I vs U which is connected to the resistor, if not error occur during simulation. After simulation I found that the surface potential closed to the excitation electrode is 697.12V while the potential at the sink electrode is 4.93e-4. I am expecting that the potential close to the excitation should be around a few volts. What went wrong here? Another thing is why I need to use ext I vs U in the connection? I had referred to the manual and could not understand. Please advice. Thank you in advanced. Regards Fazlul
Edgar Kaiser
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Posted: 1 decade ago Dec 17, 2012, 3:22 a.m. EST
Fazlul,

this is a different question and you should open a new thread for it.

Cheers
Edgar
Fazlul, this is a different question and you should open a new thread for it. Cheers Edgar
Edgar Kaiser
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Posted: 1 decade ago Dec 17, 2012, 3:25 a.m. EST
Amr,

in a stationary study you can't have AC or any time dependent sources. You can use frequency domain for harmonic sources.
For general kind of waveforms you must use a transient study. Take care that the solver time steps resolve the characteristics of the waveform.

Cheers
Edgar
Amr, in a stationary study you can't have AC or any time dependent sources. You can use frequency domain for harmonic sources. For general kind of waveforms you must use a transient study. Take care that the solver time steps resolve the characteristics of the waveform. Cheers Edgar

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