Electronics is the science that is concerned with the emission, control and flow of electrons in vacuum and matter. In electronics, circuits are designed with active electrical components, associated passive electrical components and interconnection technologies. Active components consist of transistors, integrated circuits, vacuum tubes, diodes, sensors, etc. Some passive components are resistors, capacitors and inductors. Electric circuits can be analog or digital. Analog circuits use a continuous range of current or voltage whereas digital circuits are based on discrete values of current and voltage. Electronics is of tremendous use in signal processing, information processing and telecommunication.