Abstract: A buck/boost converter is driven by a high frequency dc-to-dc flyback converter to provide substantially constant output power, independent of the output voltage, to an inductor to provide current to a load having a v-i characteristic that is suitable for use with a current power source, such as a plurality of parallely-connected LEDs. The flyback converter repetitively generates a battery-simulated output voltage that is current-limited and which may be used to charge a battery as well as to provide power to the buck/boost converter. The buck/boost converter includes a switching circuit for repetitively transferring current to the load and a current sensor circuit operating in conjunction with the switching circuit to change the state of the buck/boost converter to repetitively open the switching means and initiate release of the current to the load.

Abstract: A self-luminous safety sign with variable legend capability. A housing supports a faceplate having safety warnings or symbols thereon. Self-luminous lights, adapted to illuminate selected characters or symbols on the faceplate without external electrical connections, are selectively mounted in the housing. The lights are removable from and displaceable within the housing so that the desired characters or symbols on the faceplate can be illuminated.