When particle flow is mainly outward through the light cylinder of a rotating pulsar magnetosphere, the resulting current flow leads to very large potential drops along field lines wherever $Omega$xB vanishes (as suggested by Holloway). These occur no matter what the sign of the charge above the magnetic polar cap. For fast pulsars such a gap potential drop is limited by pair production discharge. In such models current flow into and out of the pulsar cap is always carried by particles of the same sign (-$Omega$xB) unless the magnetic polar axis is nearly perpendicular to the spin axis. For the Crab pulsar, the gap potential at breakdown is approx.10$sup 14$ V, and the resulting radiation is mainly hard X-rays and $gamma$-rays up to 10$sup 11$ eV. The latter are expected to be emitted almost perpendicular to the magnetic axis and probably, therefore, should be observed almost 90degree earlier in phase than much lower energy pulsar emission. (AIP)