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applying a periodic biphasic square waveform to a surface electrode
Posted May 2, 2013, 5:44 a.m. EDT Low-Frequency Electromagnetics Version 4.3a 2 Replies
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Dear friends,
I want to apply an AC voltage/Current to a surface electrode placed on the human skin. I need a periodic waveform with unequal on and off time. How can I apply this stimulation pulse to a surface electrode at specific frequency?(I built the desired waveform from Definition node-> Function-> Piecewise, and set the electrode voltage from Electric Potential at 5V but when I change the duration of the pulse nothing changes. Is it correct way to apply desired waveform to an electrode?)
Please help me to solve this problem.
Best regards,
I want to apply an AC voltage/Current to a surface electrode placed on the human skin. I need a periodic waveform with unequal on and off time. How can I apply this stimulation pulse to a surface electrode at specific frequency?(I built the desired waveform from Definition node-> Function-> Piecewise, and set the electrode voltage from Electric Potential at 5V but when I change the duration of the pulse nothing changes. Is it correct way to apply desired waveform to an electrode?)
Please help me to solve this problem.
Best regards,
2 Replies Last Post May 4, 2013, 7:14 a.m. EDT
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Posted:
1 decade ago
Hi
you probably need to use the time series and run a transient analysis, with a function describing your pulse (either an analytical one, or a combination of step() operators etc.)
In transient pls be aware that you need good initial conditions to avoid turn on spikes and their ringing, and that you should use a time stepping definition that have a few points during rise and fall time periods of your pulse. And then dig your way down in the solver nodes and set the time stepping to "intermediate" or "strict", and do not leave the default "free" as this will most probably skip rapidly your periodic BC conditions
Another way would be to run a frequency sweep, and then add up enough frequency components to give your special pulse. You can get offsets normally by using the special frequency stationary or frequency transient solver options (if these are available for your physics)
--
Good luck
Ivar
you probably need to use the time series and run a transient analysis, with a function describing your pulse (either an analytical one, or a combination of step() operators etc.)
In transient pls be aware that you need good initial conditions to avoid turn on spikes and their ringing, and that you should use a time stepping definition that have a few points during rise and fall time periods of your pulse. And then dig your way down in the solver nodes and set the time stepping to "intermediate" or "strict", and do not leave the default "free" as this will most probably skip rapidly your periodic BC conditions
Another way would be to run a frequency sweep, and then add up enough frequency components to give your special pulse. You can get offsets normally by using the special frequency stationary or frequency transient solver options (if these are available for your physics)
--
Good luck
Ivar
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Posted:
1 decade ago
Thank you for your reply.
You were right, I selected the time steps too large compared with pulse duration.
In my model there are different layers as different tissues and two surface electrodes place on the tissue. Could I ask you to explain more about the required boundary condition for this simulation (I mean between two layers)?
The best,
You were right, I selected the time steps too large compared with pulse duration.
In my model there are different layers as different tissues and two surface electrodes place on the tissue. Could I ask you to explain more about the required boundary condition for this simulation (I mean between two layers)?
The best,