R1 and R4 are the opposite arms of a Wheatstone bridge as

R₁ and R₄ are the opposite arms of a Wheatstone bridge as are R₃ and R₂. The source voltage is applied acr oss R₁ and R₃. Under bal anced conditions which one of the following is true?

At balance condition,
Potential at B = Potential at D
∴ V_A – i₁R₁ = V_A – i₂R₂ ...(A)

⇒	i₁	=	R₂
	i₂		R₁

Similarly, we get

⇒	i₁	=	R₃
	i₂		R₄

Equating equation (A) equation (B), we have

∴	R₂	=	R₄
	R₁		R₃