In Fig. 4.63, R1 = 500 Ohm and R3 = 200 Ohm. The bridge is balanced when R2 is a
ID: 3193386 • Letter: I
Question
In Fig. 4.63, R1 = 500 Ohm and R3 = 200 Ohm. The bridge is balanced when R2 is adjusted to be 125 Ohm. Determine the unknown resistance Rx. Solution: Using Eq. (4.30), Rx = R3/R1 R2 = 200/500 125 = 50 Ohm A Wheatstone bridge has R1 = R3 = 1 k Ohm . R2 is adjusted until no current flows through the galvanometer. At that point, R2 =3.2 k Ohm . What is the value of the unknown resistance? Answer: 3.2 k Ohm . The circuit in Fig. 4.64 represents an unbalanced bridge. If the galvanometer has a resistance of 40 Ohm, find the current through the galvanometer.Explanation / Answer
Rx = [R3/R1] *R2
= [1/1]3.2
= 3.2 Kohm