A marine warning sign, in the shape of a right
prism, having a frame forming a square of other polygonal shaped
enclosure with straight sides and open front and rear faces. In the front face is positioned an
assembly comprised of a transparent panel under which is a
graphics panel. On the obverse face of the
graphics panel is printed some desired warning indicia. A rear panel enclosed the rear face of the frame. A border, in the same shape as the frame, surrounds the indicia. The border is formed of electroluminescent tape. The electroluminescent tape illuminates when energized by an electrical
power control located within the sign. The electrical
power control is powered by a rechargeable battery which powers an a / c to d / c
inverter. The electrical
power control is switched on and off during night and day, respectively, by a circuit in the electrical power control comprised of a
comparator having a
bridge circuit with a
photoresistor as one input.
Mercury level switches also are provided to disable the electrical power control if the sign is tilted from its desired level attitude. The
inverter provides
alternating current to two leads of the electroluminescent tape, causing the electroluminescent tape to illuminate.