Starting and operating device for a high pressure discharge lamp

A starting and operating device in combination with a high pressure discharge lamp of the mercury vapor, metal halide additive type, said discharge lamp including at least one starting electrode positioned near one of the pair of spaced main electrodes within the discharge vessel;

• said starting and operating device including an ignition circuit having an inductance therein and first and second bridging circuits;
• said first bridging circuit interconnecting said starting electrode and the main electrode remote from said starting electrode and said second bridging circuit interconnecting said starting electrode and the adjacent main electrode;
• each of said first and second bridging circuits being external of said discharge vessel and said first bridging circuit comprising a current-interrupting electrical component and said second bridging circuit including a switching element whereby said circuit for ignition of the lamp is repeatedly closed and interrupted in alternation during starting and remains closed during operation of the lamp.