Abstract: A moisture barrier for radiation-responsive switches which includes an admixture of particles and forms a part of a multilamp photoflash array comprises a thin, radiation-transparent and/or translucent coating which is absorbed into the switches and envelopes the individual particles of the admixture.

Abstract: A tungsten-halogen lamp employs a slidable getter which automatically positions itself in the lowest, and thus, coolest, portion of the envelope where it is most efficient. This feature allows such lamps to be burned in a horizontal or vertical mode; the vertical mode including both base down and base up positioning.

Abstract: A photoflash unit having a plurality of flashlamps mounted on a printed circuit board containing circuitry for sequentially igniting the flashlamps in response to successive firing pulses applied thereto. The circuitry includes a plurality of solid-state switches capable of being activated by radiant energy generated during flashing of lamps located adjacent to respective switches. Initially, each of the switches has a resistance sufficiently high to provide an open circuit to the applied firing pulses, and after being activated by radiation, the switch undergoes chemical conversion to a conductive state over a finite time interval. The switches are prepared from compositions comprising admixtures of silver carbonate and/or silver oxide, silver-coated glass beads and a binder; the admixtures may also include electrically non-conductive particulate solids, such as titanium dioxide, and/or silver-coated metal beads.