Light source comprising a high pressure discharge lamp.

摘要

A high pressure sodium lamp (10), which includes a discharge tube (20) enclosing xenon at pressures in excess of 300 torr, is reliably started by the combination of an igniter (16), a conductor (12) wrapped around the discharge tube (20), and a switching circuit (14). The igniter (16) provides periodic pulses of 2500 to 4000 volts with a duration of at least one microsecond. The switching circuit (14) provides a high voltage pulse having an amplitude about equal to the amplitude of the periodic pulses and a duration much greater than the duration of the periodic pulses. The conductor (12) intensifies the electric field within the discharge tube (20). A conventional lamp ballast (18) provides ac power during starting and normal operation.