Wheastone Bridge Homework: Compute i1 and i2

[kexanie]

Homework Statement

Compute i1 and i2 in Figure a). R₃ = R₄ = 6Ω, and R₅ = R₆ = 12Ω.

Homework Equations

KVL and KCL

The Attempt at a Solution

Since R₃ / R₅ = R₄ / R₆ , it's a Wheastone Bridge and i₂ = 0, and i₁ = \frac{20}{9} A.

But my question is, why circuit in Figure b) is not equivalent to circuit in Figure a) when a) is a Wheastone Bridge?

 

[ehild]

Homework Statement

Compute i1 and i2 in Figure a). R₃ = R₄ = 6Ω, and R₅ = R₆ = 12Ω.

Homework Equations

KVL and KCL

The Attempt at a Solution

Since R₃ / R₅ = R₄ / R₆ , it's a Wheastone Bridge and i₂ = 0, and i₁ = \frac{20}{9} A.

But my question is, why circuit in Figure b) is not equivalent to circuit in Figure a) when a) is a Wheastone Bridge?

The current through the vertical wire between the two pairs of parallel resistances is not equal to I2. Consider the Nodal Law. What is I2 in a) and what is it in b). Are they identical?

ehild