High pressure lamp e.g. metal halide lamp, operating method, involves using constant direct current mode when dimness level is less than specified threshold value, where lamp is operated with low dimness level with constant direct current

摘要

The method involves utilizing constant direct current mode, when dimness level is less than specified threshold value. A commutation direct current mode is utilized, when the level is higher than the threshold value. Acoustic stabilization is made, when the level is smaller than the threshold value together with the direct current mode. The lamp is operated with low dimness level with constant direct current.