| 摘要 |
PURPOSE:To obtain a captioned lamp having a filament construction, in which a flickering phenomenon of a lamp is prevented, by making the inner diameter of a tertiary winding coil, frequency of a discharge current and a current idle period in a period of a discharge current to satisfy a specific relational expression. CONSTITUTION:A fluorescent lamp 4, which has a triple coil filament electrode while being lighted through a current-limiting circuit, where a discharge current has a current idle period, is so constituted as to satisfy a relational expression: MD3X(TO/TR)<=2 when the inner diameter of a tertiary coil of the triple coil filament is made to be MD3(mm.) while making frequency of the charged current to be TO and the current idle period in a period of the discharge current to be TR. For instance, voltage to be impressed on the terminals 1a and 1b is made to be 200-240V while making a capacitor 2 to be 3.8-4.5muF, current frequency to be 50-60Hz, a choke coil 3 to be 300mH, a circular fluorescent lamp 4 to be a lamp of 20 watt size and using a glow starter as a starting device. Further, the tertiary winding coil inner diameter is made to be ND3=0.85mm. while making to be TO/TR 2, MD3.TO/TR=1.7. |
