| 摘要 |
<p>PURPOSE: To provide a method and a stable circuit for operating a metal halide lamp suitable for an automobile by DC current to which the selectable amount of ripple is superimposed. CONSTITUTION: A high voltage pulse signal acts as a lamp starting signal. An operation circuit has a means which generates a first DC level signal and supplies it to a lamp, a means which generates a first ripple signal having a selectable amplitude and frequency, and a means which generates an operation signal by combining the first DC level signal and a first ripple signal. The operation circuit has a means which monitors the voltage of the lamp, stops the operation signal when the voltage reaches a first specified value, and stops a starting signal when the voltage reaches a second specified value or less. An operation method has a step for selecting the amplitude and the frequency of the operation signal in order to acoustically operate the lamp so that a straight arc is formed between the electrodes, and a step for frequency- modulating a signal supplied to the lamp only by the selectable amount.</p> |
