Operating device and method for operating at least one Hg low pressure discharge lamp

A method for operating at least one Hg low-pressure discharge lamp which has a first and a second electrode coil, comprising an operating device having an input for connecting a supply voltage;

• an output for connecting the at least one Hg low-pressure discharge lamp;
• a unit for providing a variable that is correlated with the Hg vapor pressure in the Hg low-pressure discharge lamp;
• a microcontroller which is coupled to said unit for providing the variable that is correlated with the Hg vapor pressure and to the output of the operating device, and is configured to provide at the output a signal for operating the at least one Hg low-pressure discharge lamp, wherein the signal is comprises at least one lamp operating parameter which is dependent on the variable that is correlated with the Hg vapor pressure, the method comprising:
• arranging at least one light receiving unit in the beam path of the at least one Hg low-pressure discharge lamp;
• capturing the emission spectrum of at least specifiable spectral ranges by means of the at least one light receiving unit which is arranged in the beam path of the at least one Hg low-pressure discharge lamp;
• and
• from the captured emission spectrum, determining the variable that is correlated with the Hg vapor pressure of the at least one Hg low-pressure discharge lamp.