  The Dirac-Born-Infled action that describes the dynamics of D branes also
allows one to compute the supersymmetries they preserve using the
Kappa-symmetry projector. The ''Lagrangian'' expression of this projector
depends on the velocity and electric fields of the branes, but not on the
corresponding conserved charges. One can also construct the projector in a
''Hamiltonian'' approach, by multiplying the conserved string, brane and
momentum charges with the corresponding gamma matrix involutions, adding them
to the mass of the brane multiplied by the unit matrix, and normalizing the
resulting expression. We show that these two procedures are equivalent.
