1977 年 1 巻 2 号 p. 2_2-2_4
The experimental investigation concerning burnout phenomena of double coiled filaments in incandescent lamps was performed. Though most of the initial hot spots in filaments observed by current pulse burning are due to diameter defects, they are not main causes of burnout. The correlation between the intially highest temperature portion burning on steady current and burnout position is high. The evidence that the irregularity of temperature distribution caused by pitch defect have bad influence on life of lamp was found.