Shown on this slide is a basic block diagram for an LED application indicating where Epcos capacitors are used. For the input protection circuit, an EMI suppression capacitor would be applied such as an X2 since it is connected to the AC mains. Aluminum electrolytic  capacitors are mainly used in the rectification circuit as a filter for smoothing the ripple current. Either standard polyester film or X2 capacitors can be used for noise suppression and filtering in the output circuit. The following  slides will cover each capacitor type in greater detail.