Electronic component

Various electronic components.

An electronic component is any basic discrete device or physical entity in an electronic system used to affect electrons or their associated fields. Electronic components are mostly industrial products, available in a singular form and are not to be confused with electrical elements, which are conceptual abstractions representing idealized electronic components.

Electronic components have a number of electrical terminals or leads. These leads connect to create an electronic circuit with a particular function (for example an amplifier, radio receiver, or oscillator). Basic electronic components may be packaged discretely, as arrays or networks of like components, or integrated inside of packages such as semiconductor integrated circuits, hybrid integrated circuits, or thick film devices. The following list of electronic components focuses on the discrete version of these components, treating such packages as components in their owner right.

Classification

Components can be classified as passive, active, or electromechanic. The strict physics definition treats passive components as ones that cannot supply energy themselves, whereas a battery would be seen as an active component since it truly acts as a source of energy.

However, electronic engineers who perform circuit analysis use a more restrictive definition of passivity. When only concerned with the energy of signals, it is convenient to ignore the so-called DC circuit and pretend that the power supplying components such as transistors or integrated circuits is absent (as if each such component had its own battery built in), though it may in reality be supplied by the DC circuit. Then, the analysis only concerns the AC circuit, an abstraction that ignores DC voltages and currents (and the power associated with them) present in the real-life circuit. This fiction, for instance, lets us view an oscillator as "producing energy" even though in reality the oscillator consumes even more energy from a DC power supply, which we have chosen to ignore. Under that restriction, we define the terms as used in circuit analysis as:

Most passive components with more than two terminals can be described in terms of two-port parameters that satisfy the principle of reciprocity—though there are rare exceptions.[2] In contrast, active components (with more than two terminals) generally lack that property.

Active components

Semiconductors

Diodes

Conduct electricity easily in one direction, among more specific behaviors.

Various examples of Light-emitting diodes

Transistors

Transistors were considered the invention of the twentieth century that changed electronic circuits forever. A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power.

Integrated circuits

Optoelectronic devices

Display technologies

Current:

Obsolete:

Vacuum tubes (valves)

A vacuum tube is based on current conduction through a vacuum (see Vacuum tube).

Amplifying tubes

Optical detectors or emitters

Discharge devices

Obsolete:

Power sources

Sources of electrical power:

Passive components

Components incapable of controlling current by means of another electrical signal are called passive devices. Resistors, capacitors, inductors, and transformers are all considered passive devices.

Resistors

SMD resistors on a backside of a PCB

Pass current in proportion to voltage (Ohm's law) and oppose current.

Capacitors

Some different capacitors for electronic equipment

Capacitors store and release electrical charge. They are used for filtering power supply lines, tuning resonant circuits, and for blocking DC voltages while passing AC signals, among numerous other uses.

Magnetic (inductive) devices

Electrical components that use magnetism in the storage and release of electrical charge through current:

Memristor

Electrical components that pass charge in proportion to magnetism or magnetic flux, and have the ability to retain a previous resistive state, hence the name of Memory plus Resistor.

Networks

Components that use more than one type of passive component:

Transducers, sensors, detectors

  1. Transducers generate physical effects when driven by an electrical signal, or vice versa.
  2. Sensors (detectors) are transducers that react to environmental conditions by changing their electrical properties or generating an electrical signal.
  3. The transducers listed here are single electronic components (as opposed to complete assemblies), and are passive (see Semiconductors and Tubes for active ones). Only the most common ones are listed here.

Antennas

Antennas transmit or receive radio waves

Assemblies, modules

Multiple electronic components assembled in a device that is in itself used as a component

Prototyping aids

Electromechanical

A quartz crystal (left) and a crystal oscillator

Piezoelectric devices , crystals, resonators

Passive components that use piezoelectric effect:

Terminals and connectors

Devices to make electrical connection

Cable assemblies

Electrical cables with connectors or terminals at their ends

2 different miniature pushbutton switches

Switches

Components that can pass current ("closed") or break the flow of current ("open"):

Protection devices

Passive components that protect circuits from excessive currents or voltages:

Mechanical accessories

Other

Obsolete

Standard symbols

On a circuit diagram, electronic devices are represented by conventional symbols. Reference designators are applied to the symbols to identify the component.

See also

References

  1. ↑ For instance, a computer could be contained inside a black box with two external terminals. It might do various calculations and signal its results by varying its resistance, but always consuming power as a resistance does. Nevertheless, it's an active component, since it relies on a power source to operate.
  2. ↑ Nonreciprocal passive devices include the gyrator (though as a truly passive component, this exists more in theoretical terms, and is usually implemented using an active circuit)—and the circulator, which is used at microwave and optical frequencies
  3. ↑ What is a Thermistor. U.S. Sensor Corp.
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