摘要:
A PORTABLE ELECTRIC TESTER ENERGIZED BY A PAIR OF SELFCONTAINED BATTERIES INCLUDING SWITCH MEANS AND A PAIR OF ELECTRIC LAMPS FOR DETERMINING FOUR APPROXIMATE RANGES OF EXTERNAL CIRCUIT RESISTANCE DEPENDENT UPON THE VISUAL INTERPRETATION OF THE LUMINOSITY OF EACH OF THE LAMPS.
摘要:
A traffic control light is provided with a supplemental lamp which is illuminable by a secondary power source. Switching means are also provided which are responsive to a failure of the primary power source to connect the supplemental lamp to the secondary source so that the supplemental lamp is illuminated in a flashing mode to continue traffic control.