Electronics

Electronics is a field of engineering and applied physics that grew out of the study and application of electricity. Electricity concerns the generation and transmission of power and uses metal conductors. Electronics manipulates the flow of electrons in a variety of ways and accomplishes this by using gases, materials like silicon and germanium that are semiconductors, and other devices like solar cells, light-emitting diodes (LEDs), masers, lasers, and microwave tubes. Electronics applications include radio, radar, television, communications systems and satellites, navigation aids and systems, control systems, space exploration vehicles, microdevices like watches, many appliances, and computers.

Resistance to the flow of current can be controlled by the conductivity of the material, dimensions over which current flows, and the applied voltage. In electronic circuits, metal films, mixtures containing carbon, and resistance wire are used to make resistors. Capacitors have the ability to retain charge and voltage and to act as conductors, especially when currents change in flow. Inductors regulate rapid changes in signals and current intensity.

Oscillators are amplifiers that receive an incoming signal and their own output as feedback (that is, also as input). They produce radio and audio signals for precision signaling, such as warning systems, telephone electronics between individual telephones and central telephone stations, computers, alarm clocks, high-frequency communications equipment, and the high-frequency transmissions of broadcasting stations.