0.0.1 ↑ 5. Hausaufgabe
0.0.1.1 ↑ Analyse eines verzweigten Stromkreises
- Gegeben
R_1 bis R_5 betragen 10{,}0 \,\Omega, R_6 sei variabel.
U = 9{,}00 \,\mathrm{V};
- Gesucht
R(R_6), I(R_6), \\ I_6(R_6), P_6(R_6)
- Rechnung
R_{4,5} = R_4 + R_5 = 2R_1;
R_{3,4,5} = \dfrac{1}{\frac{1}{R_1} + \frac{1}{R_{4,5}}} = \frac{2}{3} R_1;
R_{2,3,4,5,6} = \dfrac{1}{\frac{1}{R_2} + \frac{1}{R_{3,4,5}} + \frac{1}{R_6}} = \dfrac{1}{\frac{1}{R_6} + \frac{5}{2 R_1}};
R(R_6) = R = R_1 + R_{2,3,4,5,6} = R_1 + \dfrac{1}{\frac{1}{R_6} + \frac{5}{2 R_1}} = 10{,}0 \,\Omega + \dfrac{1}{\frac{1}{R_6} + 0{,}250 \frac{1}{\,\Omega}};
I(R_6) = I = \frac{U}{R} = \dfrac{U}{R_1 + \dfrac{1}{\frac{1}{R_6} + \frac{5}{2 R_1}}} = \dfrac{9{,}00 \,\mathrm{V}}{10{,}0 \,\Omega + \dfrac{1}{\frac{1}{R_6} + 0{,}250 \frac{1}{\,\Omega}}};
U_6(R_6) = U_6 = U_2 = \frac{R_{2,3,4,5,6}}{R_1} U_1 = \frac{R_{2,3,4,5,6}}{R_1} R_1 I_1 = R_{2,3,4,5,6} I = \dfrac{I}{\frac{1}{R_6} + \frac{5}{2 R_1}} = \dfrac{U}{\left(R_1 + \dfrac{1}{\frac{1}{R_6} + \frac{5}{2 R_1}}\right) \Biggl(\dfrac{1}{R_6} + \dfrac{5}{2 R_1}\Biggr)} = \dfrac{9{,}00 \,\mathrm{V}}{\left(10{,}0 \,\Omega + \dfrac{1}{\frac{1}{R_6} + 0{,}250 \frac{1}{\,\Omega}}\right) \Biggl(\dfrac{1}{R_6} + 0{,}250 \frac{1}{\,\Omega}\Biggr)};
\renewcommand{\arraystretch}{2.5}\begin{array}{ll}I_6(R_6) = I_6 = \frac{U_6}{R_6} & = \dfrac{U}{\left(R_1 + \dfrac{1}{\frac{1}{R_6} + \frac{5}{2 R_1}}\right) \Biggl(\dfrac{1}{R_6} + \dfrac{5}{2 R_1}\Biggr) R_6} = \\ & = \dfrac{9{,}00 \,\mathrm{V}}{\left(10{,}0 \,\Omega + \dfrac{1}{\frac{1}{R_6} + 0{,}250 \frac{1}{\,\Omega}}\right) \Biggl(\dfrac{1}{R_6} + 0{,}250 \frac{1}{\,\Omega}\Biggr) R_6};\end{array}
\renewcommand{\arraystretch}{2.5}\begin{array}{ll}P_6(R_6) = P_6 = U_6 I_6 & = \dfrac{U^2}{\left(R_1 + \dfrac{1}{\frac{1}{R_6} + \frac{5}{2 R_1}}\right)^2 \Biggl(\frac{1}{R_6} + \frac{5}{2 R_1}\Biggr)^2 R_6} = \\ & = \dfrac{81{,}0 \,\mathrm{V}^2}{\left(10{,}0 \,\Omega + \dfrac{1}{\frac{1}{R_6} + 0{,}250 \frac{1}{\,\Omega}}\right)^2 \Biggl(\dfrac{1}{R_6} + 0{,}250 \frac{1}{\,\Omega}\Biggr)^2 R_6};\end{array}
- Grenzwertbetrachtungen
\renewcommand{\arraystretch}{1.5} \begin{array}{llcl} {} \lim\limits_{R_6 \to 0 \,\Omega} & R(R_6) & = & 10{,}0 \Omega; \\ {} \lim\limits_{R_6 \to \infty \,\Omega} & R(R_6) & = & 14{,}0 \Omega; \\ {} \lim\limits_{R_6 \to 0 \,\Omega} & I(R_6) & = & 0{,}900 \,\mathrm{A}; \\ {} \lim\limits_{R_6 \to \infty \,\Omega} & I(R_6) & = & 0{,}643 \,\mathrm{A}; \\ {} \lim\limits_{R_6 \to 0 \,\Omega} & I_6(R_6) & = & 0{,}900 \,\mathrm{A}; \\ {} \lim\limits_{R_6 \to \infty \,\Omega} & I_6(R_6) & = & 0 \,\mathrm{A}; \\ {} \lim\limits_{R_6 \to 0 \,\Omega} & P_6(R_6) & = & 0 \,\mathrm{W}; \\ {} \lim\limits_{R_6 \to \infty \,\Omega} & P_6(R_6) & = & 0 \,\mathrm{W}; \end{array}
(Benötigte Zeit: 78 min (inkl. Eintippen, Grafik und Formatierung; reine Arbeitszeit 44 min))