Electromagnetic radiation emitting bulb and method using same in a portable device

An electromagnetic radiation emitting bulb, comprising a housing; one or more power input terminals disposed on that housing; a voltage converter disposed within the housing, where the voltage converter is electrically connected to the one or more power input terminals; and one or more electromagnetic radiation emitting devices disposed within the housing, where those one or more electromagnetic radiation emitting devices are electrically connected to the voltage converter. A method to emit electromagnetic radiation from a hand-carried device comprising an electromagnetic radiation emitting bulb and one or more battery cells. The method supplies first DC power having a first voltage from the one or more battery cells to the bulb, converts within the bulb the first DC power to second DC power having a second voltage, supplies within the bulb the second DC power to one or more electromagnetic radiation emitting /devices, and emits electromagnetic radiation.