Electronic devices are the devices which work on electronic variables such as power, voltage or current. These systems are used for controlling the flow of electrical currents for information processing and system control. Electronic devices contain two types of components, namely, passive components and active components. Passive components are without gain or directionality such as resistors, capacitors, diodes and inductors, whereas active components are those having gain or directionality. Active components include transistors, integrated circuits (ICs), and logic gates; whereas circuit is a passive component. Electronic systems are created to process electrical signals. The electronic systems can have a number of inputs and outputs. Some examples of an electronic system are an audio system, MP3 player and television. Electronic devices and systems are utilized for the acquisition or acceptance, processing, storage, display, analysis, protection, disposition, and transfer of information. This book outlines the applications of basic electronics devices and systems in detail. Coherent flow of topics, student-friendly language, and extensive use of examples make this book an invaluable source of knowledge.