An improved quick-disconnect switch for use in a multilamp photoflash unit containing a plurality of flashlamps and circuit means for sequentially igniting the flashlamps, in which the switch is adapted to automatically by-pass a flashlamp having an improper atmosphere therein, referred to herein as an "air" or "vacuum" lamp. The disconnect switch comprises a length of polymeric material which is rendered electrically conductive by a deposit of conductive material (e.g., aluminum) on at least a portion of the surface thereof. The conductive material has a gap disposed therein extending substantially transverse to the length thereof. The disconnect switch is severed directly by ignition of the primer from the high voltage pulse that ignites the lamp rather than by previously required direct optical energy coupling from the lamp. In an alternate embodiment, the switch may be constructed of a thin, low melting alloy member.