Electronics is the branch of science and technology concerned with controlling the flow of electric current using electronic components and circuits. Electronic systems are used in computers, mobile phones, televisions, communication equipment, alarms and many other devices.
An electronic system receives information or a signal, processes it according to a set of instructions, and produces a useful result.
A basic electronic system can be divided into three main parts:
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Input: Receives information or a signal from the user or surroundings.
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Processor: Processes the input information and determines the required action.
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Output: Produces the result of the processing.
For example, in an automatic lighting system, a sensor detects the presence of a person. The processor evaluates the signal and activates the light when the required condition is met.
Electronic systems use different components to control current and perform specific functions. Important components include resistors, diodes, transistors and integrated circuits.
Basic electronic components
Resistor
A resistor is an electronic component that opposes the flow of electric current. It is used to control current and help protect other components in a circuit. Electrical resistance is measured in ohms (Ω).
Diode
A diode is a semiconductor device that allows electric current to flow mainly in one direction. It has two terminals called the anode and the cathode. Diodes are used in electronic circuits for functions such as rectification, in which alternating current (A.C.) is converted into direct current (D.C.).
Transistor
A transistor is a semiconductor device used to control electric current. It can operate as an electronic switch or as an amplifier. In switching applications, a small input signal can control a larger current, allowing a circuit to turn a device on or off.
Integrated circuit (IC)
An integrated circuit contains many electronic components connected together on a small semiconductor chip. ICs are used in computers, calculators, communication devices and other electronic equipment.
Alternating current and direct current
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Alternating current (A.C.) changes direction periodically. Electricity supplied through the mains is generally alternating current.
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Direct current (D.C.) flows in one direction. Cells and batteries provide direct current.
A circuit that converts A.C. into D.C. is called a rectifier circuit. Diodes are important components of rectifier circuits because they allow current to pass in one direction.
Electronic systems make it possible to receive signals, process information, control electrical devices and perform automatic operations.