Quiet@Remove["Global`*"];
$HistoryLength=2;
SetDirectory[NotebookDirectory[]];

u1[t_]:=(Sqrt[2.])*230*Sin[ω*t+0.1];
u2[t_]:=(Sqrt[2.])*230*Sin[ω*t-0.1];
U1=(Sqrt[2.])*230*Exp[+0.1*I];
U2=(Sqrt[2.])*230*Exp[-0.1*I];
R1=1.;
R2=1;
mH=0.001;
L1=10mH;
L2=10mH;
Rz=15;
Lz=50mH;
Cz=47*(10^(-6));

rce={((U1-Uz)/(R1+I*ω*L1))+((U2-Uz)/(R2+I*ω*L2))==(Uz/Rz)+(Uz/(I*ω*Lz))+(Uz/(1/(I*ω*Cz)))};
uz[ω_]=Uz/.Solve[rce,Uz][[1]];

max=Quiet@FindMaximum[Abs[uz[ωmax]],{ωmax,2000}]

(*reseni ulohy c)*)
pl1=LogLogPlot[Abs[uz[ω]],{ω,1,1.5*(10^4)},AxesLabel->{"ω[(s^(-1))]","Abs[Uz] [V]"},PlotStyle->{Red,Thick},AxesOrigin->{0,0},GridLines->Automatic,PlotLabel->"UzMax= "<>ToString[max[[1]]]<>" V  pro ω= "<>ToString[ωmax/.max[[2]]]<>" (s^(-1))"]

Export["logPlot.pdf",pl1]