Electronics is the study of how to control the flow of electrons. It deals with circuits made up of components that control the flow of electricity. Electronics is a part of physics and electrical engineering.
Electrical components like transistors and relays can act as switches. This lets us use electrical circuits to process information and transmit information across long distances. Circuits can also take a weak signal (like a whisper) and amplify it (make it louder).
Most electronic systems fall into two categories:
Processing and distribution of information. These are called communications systems.
Conversion and distribution of energy. These are called control systems.One way of looking at an electronic system is to separate it into three parts.Inputs - Electrical or mechanical sensors, which take signals from the physical world (in the form of temperature, pressure, etc.) and convert them into electric current and voltage signals.Signal processing circuits - These consist of electronic components connected together to manipulate, interpret and transform the information contained in the signals.
Outputs - Actuators or other devices that transform current and voltage signals back into human readable information.
A television set, for example, has as its input a broadcast signal received from an antenna, or for cable television, a cable.Signal processing circuits inside the television set use the brightness, colour, and sound information contained in the received signal to control the television set's output devices. The display output device may be a cathode ray tube (CRT) or a plasma or liquid crystal display screen. The audio output device might be a magnetically driven audio speaker. The display output devices convert the signal processing circuits' brightness and colour information into the visible image displayed on a screen. The audio output device converts the processed sound information into sounds that can be heard by listeners.Analysis of a circuit/network involves knowing the input and the signal processing circuit, and finding out the output. Knowing the input and output and finding out or designing the signal processing part is called synthesis.