Multi-Layer Film Substrate Fr4 PCB Board Protype

Incandescent light is emitted from a wire suspended in space. Incandescent bulb-designers spent a lot of time and energy trying to redirect the light into a particular direction and beam pattern. One natural advantage of LEDs is that LED light is emitted from a surface and is already very directional - so they are a natural fit into under-counter lighting and desktop lamps. Usually the LEDs are integrated into the fixture - so there are no replaceable parts. Figure 1 is again the block diagram for the above. An MOV is once again the guardian of the AC input, and are usually sized as a percentage of the total design cost. Thus, more expensive units will warrant a larger and more effective MOV device.

One important aspect of task lighting is that it can be unplugged and is often portable. Typically housed in plastic materials that do not drain away static charge, ESD becomes a potential issue. The most vulnerable components are the LEDs themselves. Usually ICs and other electronics are protected by various components on the controller PCB, although not always. One scenario for disaster is that someone decides to move an LED desk lamp from one side of a carpeted room to the other. It is unplugged, grasped by the light-emitting end, walked across the carpet and when the user goes to plug it in, the static charge built up on the journey is discharged from their hand, through the LEDs, through the driver electronics, through the cord and back to earth. ("Honestly! It worked over there, but now it's dead!") ESD protection around the LEDs is key to the survival of these designs.