the housing 102 a first gap 185 is created between the external edge 176 of the driver circuitry 408 and the inner surface 171 where only the wire joints 702 bridge this area the first gap 185 allows for the heat generated by the driver circuitry 408 not to be exchanged via conduction with the leds located on the circuit board 402 thus insulating the first heat source with the leds acting as a second heating source heat generated by the driver circuitry 408 can be exchanged by conduction with the housing plate via convection if there is gas or air within either the first gap 185 or the second gap 177 created between an upper surface 178 of the driver circuitry 408 and the diffuser 106 for example a cap 108 can be also designed to help bridge the second gap 177 and serve as heat exchanger to evacuate heat from the driver circuitry 408 as shown at fig7 the support 173 for the toroid shaped circuit board 402 is an area made from conductive metal part of the housing 102 designed to store and transfer calorific energy via conduction from the secondary heating source to the fins 105 in the example as shown at fig6 the heating sources namely the leds and the driver circuitry 408 are distributed as evenly as possible over the volume of the housing to prevent local spikes in heat the radial and circumferential distribution of the leds is also regular and in two or more.