# current divider problem $$R_1=27kOhms ,R_2=56kOhms,R_3=50kOhms,V_s=5V$$ I'm trying to find the current thats flowing through R3, what i did was to convert the voltage source and resistors R1+R2 into a current source and then i use current divider formula to solve R3: I3=Is((R1+R2)/(R1+R2)+R3. Is that correct?

• The current through R3 is just Vs/R3. No need to make it complicated in this case. – Andrés Jun 12 '17 at 22:03

It's not correct. In this case, left circuit and right circuit work independent: the current flowing through the left part (R3) does not depend on the current that flows through the right side (R1, R2). As Andres just pointed out, I3=Vs/R3 simulate this circuit – Schematic created using CircuitLab

Running the simulation above matches the analytical result:

$$i_1 = \frac {5 \ \text{V}} {27 \ \text{k}\Omega + 56 \ \text{k}\Omega} = 60.2 \ \mu\text{A}$$

$$i_3 = \frac {5 \ \text{V}} {50 \ \text{k}\Omega} = 100 \ \mu\text{A}$$

$$V_{\text{out}} = i_1 R_2 = 3.37 \ \text{V}$$