62), we obtain,
1
2
2
1
I
R
I
R
=
whereas from Eq (3 63), we obtain,
1
4
2
3
I
R
I
R
=
Hence, we obtain the condition
2
4
1
3
R
R
R
=R
[3 64(a)]
 This last equation relating the four resistors is called the balance
condition for the galvanometer to give zero or null deflection