An electrical instrument includes a proximal section, a distal section, and a flex circuit. The distal section is coupled to the proximal section at a swivel interface to enable rotational independence of the distal section relative to the proximal section. The flex circuit spans the swivel interface between the proximal section and the distal section and provides electrical communication between the proximal section and the distal section even when one of the proximal section and the distal section is rotated relative to the other.