The light is emitted from e.g. eight short fluorescent tubes (2) arranged with their axes parallel around a ring, with a tubular housing (4) in its centre for components of the electronic switch unit. Within the ring, four rigid connectors (30) are arranged side by side for contact with resilient conductors (32) soldered to e.g. a printed circuit board (36). The connectors (30) are slotted (35) for automatic attachment of wires extending from the bases of the fluorescent tubes (2).
