An active device is an electrical device that requires a source of energy, such as electricity, to operate. It has an output signal that is a function of present and past input signals. Examples of active devices include power supplies, transistors, light-emitting diodes (LEDs), amplifiers, and transmitters.
A power supply is an active device used to convert electrical power from a source, such as a battery, to an output voltage and/or current level that can be used by other electrical components. Transistors are active semiconductor devices used to amplify or switch electrical signals, and are often used to control the flow of electricity in circuits. LEDs are active devices used to convert electrical energy into light energy, and are often used for lighting and in electronic displays. Amplifiers are active devices used to increase the amplitude of an input signal and are used in audio and communication systems. Transmitters are active devices used to broadcast signals over a distance, such as in radio and television systems.
Active devices are typically found in cables and other electrical systems. Cables are used to connect two or more devices, allowing electrical signals to travel between them. Active devices are often used in cables to control the flow of electricity, adjust the signal levels, or amplify the signal strength.
Active devices are essential components of almost all electrical systems, allowing them to function properly and efficiently. Without active devices, the majority of modern electronics and communication systems would be unable to operate.