GAS-DISCHARGE LAMP TYPE RECOGNITION BASED ON BUILT-IN LAMP ELECTRICAL PROPERTIES

摘要

A gas discharge lamp has an impedance element such as a capacitor connected to at least one electrode heater, to produce a heater impedance which falls within a range which is unique to lamps of that lamp type. An electronic ballast for operating such lamp has a lamp type detection circuit which measures the cold heater impedance and identifies the corresponding lamp type. The ballast may sample the heater circuit current to determine resistive and reactive components to aid in lamp type identification and to control heater warm-up. The ballast may include a separate inverter for heater power, and control heater power separate from arc power after lamp ignition.