| 摘要 |
PURPOSE:To transfer a lamp certainly to glow arc condition by impressing a voltage which suits the glow potential generated in the lamp and which is not excessive. CONSTITUTION:At starting, a steep current flows cyclicly to the primary side coil L1 of a transformer 6, and thereby a high voltage is generated in the secondary side coils L2, L3 of the transformer 6, and capacitors 13, 15 are charged with a high voltage via diodes 12, 15. Each time the charging voltage of the capacitor 15 reaches the voltage to break the discharge gap 16, a high voltage pulse is generated in the secondary coils L5, L6 of another transformer 7 so that a high pressure discharge lamp 21 goes in break-down. If the charge voltage (backup voltage) of the capacitor 13 has risen above the glow potential in the period the same as this operation, a rush current flows from the capacitor 13 to the high pressure discharge lamp 21 in the glow discharge condition, which is thereby transferred to the glow arc condition, so that a voltage which suits the glow potential and is not excessive is impressed on the discharge lamp 21. |
