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generate pulse train

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Dear ivar

I am sorry for repeated questions. i need more details to get the pulse train correct (the pulse train amp.=15000 and freq.= 1000hz)

first i open function and get recangle and in rect1 ( i put the lower limit =0 and upper limit =0.5e-3 and
transition = 20 e-6)

then i open parameters and i put in names ' DV( voltage) ' and in expressions (15000* rect1(mod((t[1/s],1e-3)) ( i don't find plot button to can check my pulse train).

Then i don't know where i can put time stepping to generate the pulse train


please help me

3 Replies Last Post 2012年1月13日 GMT-5 11:40
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 2012年1月13日 GMT-5 02:41
Hello

pls do not confuse "Parameters" (global static constants defined once at solver run) and Variables defined by expressions built on other variables and parameters of all sorts, and the operators and functions from the Defintions node. You can only plot operators and functions in their definition node (by defining a range).

You then use the operators for variables or postprocessing use

Note to a variable has a domain of application, that is global scalars are separate, most others are in fact fields depending on the spatial and or time predefined variables such as x,y,z,t (+r in 2D-axi)

Check the doc, and read throug carefully, its important to understand the COMSOL notation

--
Good luck
Ivar
Hello pls do not confuse "Parameters" (global static constants defined once at solver run) and Variables defined by expressions built on other variables and parameters of all sorts, and the operators and functions from the Defintions node. You can only plot operators and functions in their definition node (by defining a range). You then use the operators for variables or postprocessing use Note to a variable has a domain of application, that is global scalars are separate, most others are in fact fields depending on the spatial and or time predefined variables such as x,y,z,t (+r in 2D-axi) Check the doc, and read throug carefully, its important to understand the COMSOL notation -- Good luck Ivar

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Posted: 1 decade ago 2012年1月13日 GMT-5 07:13
Dear Ivar

thanks i understand.

but how i define the pulse train in 5 hours?


another question

where can i define time stepping?


thanks
Dear Ivar thanks i understand. but how i define the pulse train in 5 hours? another question where can i define time stepping? thanks

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 2012年1月13日 GMT-5 11:40
Hi

The length of the analysis is defined in the time solver node, the simulation range

the time step type Free, intermediate or strict in the ... solver ... Time solver sbnode (note the tab might be "closed" by default in the window, select it to see the details


--
Good luck
Ivar
Hi The length of the analysis is defined in the time solver node, the simulation range the time step type Free, intermediate or strict in the ... solver ... Time solver sbnode (note the tab might be "closed" by default in the window, select it to see the details -- Good luck Ivar

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