How to find Equivalent resistance
- First of all, identify the series components
- After this identify the parallel components
- Solve series components
- Solve parallel components
- Replace the series resistors by the new equivalent resistance
- Replace parallel resistors by the new equivalent resistance
- Again solve all components to obtain equivalent resistance
Let’s solve the example of figure 1.
Step 1: R1 and R2 are in series
Step 2: R3, R4, and R5 are in parallel
Step 3: Req (s) = R1 + R2 = 5 + 5 = 10 ohms
Step 4: Req (p) = 1/((1/R1) + (1/R2) + (1/R3)) = 1/((1/9) + (1/9) + (1/9)); Req = 3 ohms
Step 5 & 6: Finally Req (s) and Req (p) are in series
Step 7: Solving Req (s) and Req (p) in series yields final equivalent resistance of 13 ohms.
Req = Req (s) + Req (p) = 10 + 3 = 13 ohms