circuit
92 to apply a torque to the rotary actuator 30 is further reduced by establishing a geometry for the second portion 186 of the first flexible circuit 92 that results in a substantially radial force being applied to the rotary actuator 30. The radial
force, in contrast to a tangential or torque producing force, does not substantially affect the position of the transducers 28a, 28b, relative to the hard disk 24. The geometry of the second portion 186 of the first flexible circuit 92 is best described
by analyzing the problem in terms of given parameters and the boundary conditions of the first end 186 and the second end 192 of the second portion 186 of the first flexible circuit 92. The given parameters of the problem are the flexuremodulus and the
length of the second portion 186 of the flexible circuit 92. Relative to the first end 188 of the second portion 186 of the first flexible circuit 92, the relevant boundary conditions are the angle through which the rotary actuator 30 turns and the
distance from the axis of rotation to the exterior surface 190 of the rotary actuator 30 where the first end 188 is attached. The boundary condition relating to the second end 192 of the second portion 186 of the first flexible circuit 92 is that it
must be fixed relative to the axis of rotation of the actuator 30. Given these boundary conditions, a double or S-shaped curve can be imposed upon the second portion 186 of the flexible circuit 92 that results in