Method for operating at least one low-pressure discharge lamp and operating device for at least one low-pressure discharge lamp

An operating device for at least one low-pressure discharge lamp having

• a half-bridge inverter, to which is connected a load circuit in which electric connections for at least one low-pressure discharge lamp and at least one half-bridge capacitor are arranged,
• a first measuring apparatus for measuring a first voltage which is proportional to the electric power injected into said half-bridge inverter,
• a second measuring apparatus for measuring a second voltage which is proportional to the voltage drop across said at least one half-bridge capacitor,
• a third measuring apparatus for measuring a third voltage which is proportional to the r.m.s. value of the running voltage of said at least one low-pressure discharge lamp,
• a fourth measuring apparatus for measuring a fourth voltage which is proportional to the supply voltage of said half-bridge inverter,
• an evaluation unit which is connected to the outputs of said measuring apparatuses and comprises a program-controlled microcontroller and which serves the purpose of evaluating said first to fourth voltage as well as of controlling said half-bridge inverter as a function of the result of the evaluation.