The ornamental design for a “circular connector,” as shown and described.
FIG. 1 is a perspective view of a “circular connector” showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is a front view showing the practical usage thereof.
The dashed line immediately adjacent to the shaded inner-ring surface at the front in FIG. 1 indicates a boundary of the claimed design while all other dashed lines show environment. The dashed lines form no part of the claimed design.