Dual-frequency resonant circuit for discharge lamp ignition - is fed from inverter at upper resonant frequency for starting and lower frequency for continuous operation

摘要

The lamp (GE) is supplied with AC from an invertor (20) via a series resonant circuit comprising two capacitors (CO,C1) and a small inductor (L1) giving a more rapid current increase after ignition. The AC frequency is reduced from an initial value slightly higher than the upper resonant frequency of 42 kHz, to a steady value close to the lower resonant frequency of 23 kHz. The glow discharge is quickly succeeded by a stable normal discharge at that frequency. ADVANTAGE - Cold lamp can be started and operated carefully in accordance with specification, esp. in explosive atmos..