To positionally stabilize the arc spot in a super-high pressure discharge lamp which is filled with at least 0.20 mg/mm.sup.3 of mercury and to prevent the formation of so-called flicker, in an operation device having a high pressure discharge lamp and a feed device, the feed device of the high pressure discharge lamp supplies a frequency in the range from 60 Hz to 1000 Hz as the stationary operating frequency and a low frequency, in a frequency range of from 5 Hz to 200 Hz is inserted which has an inserted length of from one half period to five periods, and an inserting period of from 0.01 seconds to 120 seconds, into the alternating current of the stationary operating frequency. Furthermore, the parameters of the low frequency are changed according to changes of the operating voltage of the discharge lamp.

 
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> High pressure mercury lamps and sealing members therefor

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