Iti voi pune 2 imagini, una a ta modificata unde vei vedea cu ce cifre am notat rezistoarele si a doua cu un circuit simplu.
Se da:
R1=R2=R3=R4=R5=R
Re=?
Formule:
[tex]\frac{1}{Re}=\frac{1}{Re_{1234}}+\frac{1}{R_{5}}\\ \\
R_{5}=R\\ \\
Re_{1234}=Re_{123}+R_{4}\\ \\
R_{4}=R\\ \\
\frac{1}{Re_{123}}=\frac{1}{R_{12}}+\frac{1}{R_{3}}\\ \\
\frac{1}{R_{3}}=\frac{1}{R}\\ \\
\frac{1}{R_{12}}=\frac{1}{R_{1}+R_{2}}=\frac{1}{2R}\\ \\
\frac{1}{Re_{123}}=\frac{1}{2R}+\frac{1}{R}\\ \\
\frac{1}{Re_{123}}=\frac{3}{2R}\\ \\
Re_{123}=\frac{2R}{3}\\ \\
Re_{1234}=\frac{2R}{3}+R=\frac{5R}{3}\\ \\
\frac{1}{Re_{1234}}=\frac{3}{5R}\\ \\
[/tex]
[tex]\frac{1}{Re}=\frac{3}{5R}+\frac{1}{R}\\ \\
\frac{1}{Re}=\frac{8}{5R}\\ \\ Re=\frac{5R}{8}\\ \\[/tex]
