Abstract: A disclosed method includes: setting a connector of an acquisition circuit and an associated capacitor to a predetermined potential; providing an energy pulse of a predetermined first time duration to the connector; at a time occurring substantially at a predetermined second time duration after an end of the predetermined first time duration of the energy pulse, coupling the associated capacitor and the connector of the acquisition circuit; and sampling a voltage being exhibited across the associated capacitor.

Abstract: A disclosed method includes: setting a connector of an acquisition circuit and an associated capacitor to a predetermined potential; providing an energy pulse of a predetermined first time duration to the connector; at a time occurring substantially at a predetermined second time duration after an end of the predetermined first time duration of the energy pulse, coupling the associated capacitor and the connector of the acquisition circuit; and sampling a voltage being exhibited across the associated capacitor.

Abstract: The invention relates to a flame monitor for an oil- or gas-operated burner, having a photosensor which detects the optical flame radiation and an evaluation circuit which is connected downstream of said photosensor and ascertains whether the radiation received by the photosensor corresponds to that of a burning flame and, in the event of a negative result, generates a switch-off signal for the fuel supply, wherein the evaluation circuit determines the number of zero crossings of the processed signal of the photosensor within a predetermined unit of time and compares it with a predetermined limit value, a switch-off signal for the fuel supply being generated when said limit value is undershot, the signal of the photosensor, freed from the DC voltage component and noise, being processed by corresponding amplification to form square-wave pulses.

Abstract: The invention relates to a flame monitor for an oil- or gas-operated burner, having a photosensor which detects the optical flame radiation and an evaluation circuit which is connected downstream of said photosensor and ascertains whether the radiation received by the photosensor corresponds to that of a burning flame and, in the event of a negative result, generates a switch-off signal for the fuel supply, wherein the evaluation circuit determines the number of zero crossings of the processed signal of the photosensor within a predetermined unit of time and compares it with a predetermined limit value, a switch-off signal for the fuel supply being generated when said limit value is undershot, the signal of the photosensor, freed from the DC voltage component and noise, being processed by corresponding amplification to form square-wave pulses.