An electronic component is any basic discrete
electronic device or physical entity part of 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 and elements. A datasheet for an electronic component is a technical document that provides detailed information about the component's specifications, characteristics, and performance.
Electronic components have a number of
electrical terminals or
leads. These leads connect to other electrical components, often over wire, 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
semiconductorintegrated 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 own 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:
Active components rely on a source of energy (usually from the DC circuit, which we have chosen to ignore) and usually can inject power into a circuit, though this is not part of the definition.[1] Active components include amplifying components such as
transistors, triode
vacuum tubes (valves), and
tunnel diodes.
Passive components cannot introduce net energy into the circuit. They also cannot rely on a source of power, except for what is available from the (AC) circuit they are connected to. As a consequence, they cannot amplify (increase the power of a signal), although they may increase a voltage or current (such as is done by a transformer or resonant circuit). Passive components include two-terminal components such as resistors, capacitors, inductors, and transformers.
Electromechanical components can carry out electrical operations by using moving parts or by using electrical connections.
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
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.
Tunnel diode - very fast diode based on quantum mechanical tunneling
Integrated circuits
Integrated Circuits can serve a variety of purposes, including acting as a timer, performing digital to analog conversion, performing amplification, or being used for logical operations.
OLED (similar to an LCD, but each pixel generates its own light, can be made flexible or transparent)
Micro-LED (similar to OLED, but uses inorganic
LEDs instead of organic ones, does not suffer from
screen burn-in, however it cannot be made flexible or transparent)
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
Pass current in proportion to voltage (
Ohm's law) and oppose current.
Power
resistor – larger to safely dissipate heat generated
SIP or
DIP resistor network – array of resistors in one package
Variable resistor
Rheostat – two-terminal variable resistor (often for high power)
Potentiometer – three-terminal variable resistor (variable voltage divider)
Trim pot – small potentiometer, usually for internal adjustments
Thermistor – thermally sensitive resistor whose prime function is to exhibit a large, predictable and precise change in electrical resistance when subjected to a corresponding change in body temperature.[5]
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.
Varicap diode – AC capacitance varies according to the DC voltage applied
Integrated passive devices
Integrated passive devices are passive devices integrated within one distinct package. They take up less space than equivalent combinations of discrete components.
Magnetic (inductive) devices
Electrical components that use magnetism in the storage and release of electrical charge through current:
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.
LC Network – forms an
LC circuit, used in tunable transformers and RFI filters.
Transducers, sensors, detectors
Transducers generate physical effects when driven by an electrical signal, or vice versa.
Sensors (detectors) are transducers that react to environmental conditions by changing their electrical properties or generating an electrical signal.
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.
Spark gap – electrodes with a gap to arc over at a high voltage
Lightning arrester – spark gap used to protect against lightning strikes
Recloser – automatic switch that opens on an overcurrent (fault) condition, then closes to check if the fault is cleared, and repeats this process a specified number of times before maintaining the open position until it is manually closed
On a
circuit diagram, electronic devices are represented by conventional symbols.
Reference designators are applied to the symbols to identify the components.
^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 resistance does. Nevertheless, it is an active component, since it relies on a power source to operate.
^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