Abstract: The invention relates to a supply coupling of a fluorescent lamp used for supervising the operation and condition of a lamp circuit, particularly a supply coupling in connection with an electronic coupling device wherein the power required by the lamp circuit is supplied to the coupling by a transformer. The supply coupling comprises a supply transformer (T1), a resonance circuit comprising the secondary coil (N2) of the transformer (T1) and a capacitor (C1) connected in parallel with the secondary coil, and a fluorescent tube (Lamp 1) connected in parallel with the resonance circuit and comprising fluorescent cathodes (F1, F2).

Abstract: A control gear for fluorescent lamps, which comprises two or more lamp circuits for igniting and burning fluorescent lamps, the lamp circuits comprising supply and ignition components (L1, C1; L2, C2) specific for each lamp, and a supply line (Vdc) which is arranged to supply voltage to the lamp circuits. The control gear also comprises a switching element (S1) connected to the supply line and common to all lamp circuits, which element is arranged to stop the supply of all lamp circuits, lamp circuit-specific switching elements (S2, S3) arranged to control the voltage of the lamps in the lamp circuits, a control unit (A) which is arranged to control the common switching element (S1) and the lamp circuit-specific switching elements (S2, S3), and lamp circuit-specific circuits (B2, B2) identifying defective fluorescent lamps, which identifying circuits are arranged to transmit information on defective fluorescent lamps to the control unit (A).

Abstract: An electronic control circuit for adjusting the control voltage of a device to be controlled, the control circuit comprising a primary coil, a control bus comprising means for adjusting the control voltage, parallel-connected with the first capacitor, the paralleling being further series-connected with the first secondary coil and a first control diode, and a control voltage supply circuit comprising a series-connected second secondary coil, a second control diode and a second capacitor. The primary coil is connected between a first node and a second node of the device to be controlled, and the nodes in the connection are selected such that the current in an electric circuit between them at least momentarily reaches the value zero.

Abstract: The invention relates to a method and a system for collecting information on the operating state from several devices connected in parallel to the same electric circuit, e.g. from safety lights connected to the same array of safety lights, each of the devices being provided with members for receiving an enquiry about the operating state of the device via the electric circuit from a testing unit and for sending a message indicating the information on the operating state to the testing unit via the electric circuit in response to the enquiry sent from the testing unit.