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How to add an AC sinusoidal volatage in a simple conductor?

Posted Aug 8, 2021, 7:28 p.m. EDT Electromagnetic Heating, Low-Frequency Electromagnetics, MEMS & Nanotechnology Version 5.6 6 Replies

Ekram Hossain Khan
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Hello,

I am working on an acoustic cantilever sensor where I want to how much is the sensor heated with the current flow in the conducting wire, and consequently how does the cantilever deflect. (Similar to microresistor beam)

I have studied the deflection of the cantilever by applying DC Electric Potential across the conducting wire. I used "Electric Current (ec)" as Physics and "Stationary" as Study.

Now, I want to apply AC sinusoidal voltage across the wire. However, I cannot find any options for sinusoidal source under "Electric Current" module.

Kindly, give me some suggestions how can I apply AC sinusoidal voltage or current across the conducting wire. Note that, there is only internal resistance of the conducting wire, no external resistance or reactance.

Thanks in advance.

6 Replies Last Post Aug 10, 2021, 9:16 a.m. EDT
Dennis Brown
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Posted: 4 years ago Aug 9, 2021, 8:19 a.m. EDT

Hi,

you will need to add the circuit option to the physics. i attached a screen shot of what needs to be done based on limited information. it should get you started. in ec, you add a terminal and change it to use a circuit. you then need to add a voltage source and an external coupling feature to the circuit node.

Hi, you will need to add the circuit option to the physics. i attached a screen shot of what needs to be done based on limited information. it should get you started. in ec, you add a terminal and change it to use a circuit. you then need to add a voltage source and an external coupling feature to the circuit node.

Attachments:

Ekram Hossain Khan
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Posted: 4 years ago Aug 9, 2021, 3:08 p.m. EDT

Hello Mr. Brown,

Thank you very much for your reply. However, I could not understand how to select nodes and what nodes "0", "1", "2" or "p", "n" mean.

I have attached the photo of the design that I am currently working on. The comsol file can be found here: https://www.comsol.com/model/microresistor-beam-366

I want to connect positive node of the voltage source to one end and negative node to the other end of the beam, so that an AC sinusoidal current flows through the microresistor beam. (Note: There are no semiconductors, the beam is made of Aluminium)

Kindly give me a direction how can I do that.

Best regards, Ekram.

Hello Mr. Brown, Thank you very much for your reply. However, I could not understand how to select nodes and what nodes "0", "1", "2" or "p", "n" mean. I have attached the photo of the design that I am currently working on. The comsol file can be found here: https://www.comsol.com/model/microresistor-beam-366 I want to connect positive node of the voltage source to one end and negative node to the other end of the beam, so that an AC sinusoidal current flows through the microresistor beam. (Note: There are no semiconductors, the beam is made of Aluminium) Kindly give me a direction how can I do that. Best regards, Ekram.

Attachments:

Dennis Brown
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Posted: 4 years ago Aug 9, 2021, 4:20 p.m. EDT

you will need to understand what a netlist is and how to implement it. there are many tutorials on the internet that show this. probably a lot of youtube videos as well.

here is one example:

https://www.allaboutcircuits.com/textbook/reference/chpt-7/example-circuits-and-netlists/

from your picture, it seems you want to apply a source to a floating object. i would suggest setting up the problem to ground one side to get something running. you would then have to modify the simulation to suit your needs. in any case, you will need two terminals in the physics similar to what i showed. you will also need to use two couplings.

you will need to understand what a netlist is and how to implement it. there are many tutorials on the internet that show this. probably a lot of youtube videos as well. here is one example: https://www.allaboutcircuits.com/textbook/reference/chpt-7/example-circuits-and-netlists/ from your picture, it seems you want to apply a source to a floating object. i would suggest setting up the problem to ground one side to get something running. you would then have to modify the simulation to suit your needs. in any case, you will need two terminals in the physics similar to what i showed. you will also need to use two couplings.
Edgar J. Kaiser Certified Consultant
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Posted: 4 years ago Aug 10, 2021, 4:25 a.m. EDT
Updated: 4 years ago Aug 10, 2021, 4:40 a.m. EDT

Ekram,

you don't need the circuit physics. Just make the Electric Potential subnode time dependent like V0 * sin(omega * t) and run a time dependent study. Make sure the time stepping resolves the waveform.

Cheers Edgar

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Ekram, you don't need the circuit physics. Just make the Electric Potential subnode time dependent like V0 * sin(omega * t) and run a time dependent study. Make sure the time stepping resolves the waveform. Cheers Edgar
Dennis Brown
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Posted: 4 years ago Aug 10, 2021, 8:15 a.m. EDT

Thanks Edgar. After I had posted my response I had realized that circuits is not strictly needed. Hard habits die hard.

Thanks Edgar. After I had posted my response I had realized that circuits is not strictly needed. Hard habits die hard.
Ekram Hossain Khan
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Posted: 4 years ago Aug 10, 2021, 9:16 a.m. EDT

Mr. Kaiser and Mr. Brown,

Many thanks to both of you for your valuable suggestions.

Mr. Kaiser and Mr. Brown, Many thanks to both of you for your valuable suggestions.

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