In a parallel circuit, how does the current in each branch relate to total current?

In a parallel circuit, how does the current in each branch relate to total current?

• A. The total current is less than any branch current
• B. The total current is the sum of branch currents; voltage across each branch is the same
• C. The total current is equal to the largest branch current
• D. The total current is twice the branch current

Answer: (B)

In a parallel circuit, the current from the source splits among the branches, while the voltage across each branch is the same as the source. Because current must be conserved at the junctions, the currents in the branches add together to form the total current. So the total current is the sum of the branch currents. If each branch draws I1, I2, etc., then I_total = I1 + I2 + ... . With the same voltage across branches, each branch current is I_branch = V / R_branch, and I_total = V(1/R1 + 1/R2 + ...). For example, if one branch carries 2 A and another carries 3 A, the total supply current is 5 A. The total current isn’t determined by the largest branch or by a fixed multiple of a single branch; it depends on all branches.

In a parallel circuit, the current from the source splits among the branches, while the voltage across each branch is the same as the source. Because current must be conserved at the junctions, the currents in the branches add together to form the total current. So the total current is the sum of the branch currents.

If each branch draws I1, I2, etc., then I_total = I1 + I2 + ... . With the same voltage across branches, each branch current is I_branch = V / R_branch, and I_total = V(1/R1 + 1/R2 + ...).

For example, if one branch carries 2 A and another carries 3 A, the total supply current is 5 A. The total current isn’t determined by the largest branch or by a fixed multiple of a single branch; it depends on all branches.