Henri,
you gave two examples with two different values of R: 40 in the first case
and 1000 in the second. In the case with R=1000, the resonance is so damped
that the peak at 1 / sqrt(LC) has disappeared, and the curve simply bends
downwards.
You should define your frequency correctly, like fr=
2*pi*linspace(0,2ω,1000) or you should define your formula correctly y =
abs(1 ./ (1+im*2*pi*fr*R*C-(2*pi*fr).^2*L*C)). Please do not mix angular
frequency and frequency, because you are in troubles: I have been there.
michele
On Thu, Jun 16, 2016 at 3:13 PM, Henri Girard <henri.gir...@gmail.com>
wrote:
> My new tentative (which is not working)
> using Plots
> R=1000;L=1/pi*360E-2;C=1/(pi*360E+2)
> w=1/sqrt(L*C)
> f=1/(2*pi*sqrt(L*C))
> omega=linspace(-f,f)
> y=abs(1./(1+im.*omega.*R.*C-omega.*omega.*L.*C));
> plot(omega,y,title="Fréquence de résonance",
> bg=RGB(.2,.2,.2),xlabel ="Hz",ylabel = "Ω")
> ---------------------------------------
> Working plot in sage,( I think the difference is var("f") and omega
> which is a symbolic variable
> R=30;L=1/pi*360E-2;C=1/(pi*360E+2)
> var("f")
> omega=2*pi*f
> w=1/(sqrt(L*C))
> Fr=1/(2*pi*sqrt(L*C))
> q=plot(abs(1/(1+i*omega*R*C-omega*omega*L*C)),
> omega,0,100,figsize=4,frame=True,
> fontsize=8,axes=False,color="red")
> show(q)
> print"Fréquence de résonance = ",round(Fr)," Hz"
> Le jeudi 16 juin 2016 09:22:12 UTC+2, Henri Girard a écrit :
>>
>> Hi,
>> When I make my plots I have two plots, but before I hadn't this...
>> w is the resoning frequency, but it should appear at 0 (zéro) not at
>> extrem ?
>> Any help, I already ask for help with pyplot, this link :
>> https://groups.google.com/forum/#!topic/julia-users/EJSvutfdEus, which
>> works fine for angular pulsation, but I want frequency resonance with Plots
>> because I guess I can make more beautifull graphic (anyway I don't know
>> well PyPlot or Plots). I succeeded once with pyplot but after an error I
>> couldn't find it back !
>> Bad luck :)
>> Kind regards
>> HG
>>
>> using Plots
>> pyplot(reuse=true)
>> z=10;u=0.02;s=0.02;w=1/(2*pi*sqrt(u*s))
>> f=linspace(-30,30)
>> y=abs(1./(1+im.*f.*z.*s-f.*f.*u.*s));
>> #fig = figure("Angle")
>> plot(f, y)
>>
>
