Question

Calculati rezistenta echivalenta pt figura de mai jos (in functie de R) .Am mare nevoie de ajutor...oricum incerc imi ies rezultate diferite... :))

3c606a9b5491eabf33727fa39fcdda06.docx

Answer 1

E o chestiune grea, mai intii trebuie sa faci un circuit mai simplu, ca sa-ti dai seama ce e in serie si ce e in paralel. Ti-am facut circuitul in paint.
Acum rezolvarea:
Rechivalent o sa notez cu Re si R cu cifre, cifrele le vezi pe desen, o sa-mi fie mai usor sa-ti explic si R1=R2=R3=R4=R5=R6=R7=R
Formule:
[tex]\frac{1}{Re}= \frac{1}{R1234}+ \frac{1}{R5}+ \frac{1}{R6789}\\ 1)a)R1234=R123+R4\\ \frac{1}{R123}= \frac{1}{R12}+ \frac{1}{R3}\\ \frac{1}{R123}= \frac{1}{2R}+ \frac{1}{R}\\ \frac{1}{R123}= \frac{3}{2R}\\ R123= \frac{2R}{3}\\ b)R4=R\\ Din:a);b)=\ \textgreater \ \\ R1234= \frac{2R}{3}+R\\ R1234= \frac{5R}{3}\\ 2)R5=R\\ [/tex] .[tex]3)a)R6789=R678+R9\\ \frac{1}{R678}= \frac{1}{R78}+ \frac{1}{R6}\\ \frac{1}{R678}= \frac{1}{2R}+ \frac{1}{R}\\ \frac{1}{R678}= \frac{3}{2R}\\ R678= \frac{2R}{3}\\ b)R6=R\\ Din:a);b)=\ \textgreater \ \\ R6789= \frac{2R}{3}+R\\ R6789= \frac{5R}{3}\\[/tex]
Acum inlocuim in prima formula folosind 1) 2) si 3)
[tex] \frac{1}{Re}= 1/( \frac{5R}{3} )+ \frac{1}{R}+ 1/( \frac{5R}{3} )\\ \frac{1}{Re}= \frac{3}{5R}+ \frac{1}{R} + \frac{3}{5R}\\ \frac{1}{Re}= \frac{11}{5R}\\ Re= \frac{5R}{11} .[/tex]