Recall from the discussion on Bridges that the relationship between bridge output voltage and input voltage is given by:
(1")
In the most general case, the resistance of each arm could be active; the resistance in each arm is therefore variable. Taking the derivative of Equation 1" yields:
(2")
Evaluating Equation 2" yields:
(3")
Since the resistances of each leg of the bridge are nominally equal to R, Equation 3" becomes:
(4")
Which becomes:
(1)
