Various electronic components, with a 15 cm ruler to scale.
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. Discrete circuits are made of individual electronic components that only perform one function each as packaged, which are known as discrete components, although strictly the term discrete component refers to such a component with semiconductor material such as individual transistors.[1][2][3]
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.[4] 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.[5] 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
SMD resistors on the backside of a PCB
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)[8]
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.[9]
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.
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
