Hellenica World

Electronic component

An electronic component is a basic electronic element and may be available in a discrete form having two or more electrical terminals (or leads). These are intended to be connected together, usually by soldering to a printed circuit board, in order 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 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

A component may be classified as passive or active. 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 performing circuit analysis use a more restrictive definition of passivity. When we are only concerned with the energy due to 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) although it may in reality be supplied by the DC circuit which we are ignoring. Then the analysis only concerns the so-called AC circuit, an abstraction which ignores the DC voltages and currents (and the power associated with them) present in the real-life circuit. This fiction, for instance, allows us to view an oscillator as "producing energy" even though in reality the oscillator consumes even more energy from a power supply, obtained through the DC circuit which we have chosen to ignore. Under that restriction we define the terms as used in circuit analysis as follows:

Passive components are ones which cannot introduce net energy into the circuit they are connected to. 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 are unable to amplify (increase the power of a signal), although they may well increase a voltage or current such as is done by a transformer or resonant circuit. Among passive components are familiar two-terminal components such as resistors, capacitors, inductors, and most sorts of diodes.
Active components rely on a source of energy (usually from the DC circuit, which we have chosen to ignore) and are usually able to inject power into a circuit although this is not part of the definition[1]. This includes amplifying components such as transistors, triode vacuum tubes (valves), and tunnel diodes.

Passive components can be further divided into lossless and lossy components:

Lossless components do not have a net power flow into or out of the component. This would include ideal capacitors, inductors, transformers, and the (theoretical) gyrator.
Lossy or dissipative components do not have that property and generally absorb power from the external circuit over time. The prototypical example is the resistor. In practice all non-ideal passive components are at least a little lossy, but these are typically modeled in circuit analysis as consisting of an ideal lossless component with an attached resistor to account for the loss.

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

Note that these distinctions only apply to components listed below which would be modeled as elements within circuit analysis. Practical items which act as transducers or have other connections to the outside world such as switches, cannot be subject to this form of classification since they defy the view of the electronic circuit as a closed system.

Components

Terminals and connectors

Devices to make electrical connection

Terminal
Connector
Socket
Screw terminal, Terminal Blocks
Header

Cable assemblies

Cables with connectors or terminals at their ends

Power cord
Patch cord
Test lead

Switches

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

Switch - Manually operated switch.
Electrical description: SPST, SPDT, DPST, DPDT, NPNT (general)
Technology: slide switches, toggle switches, rocker switches, rotary switches, pushbutton switches
Keypad - Array of pushbutton switches
DIP switch - Small array of switches for internal configuration settings
Footswitch - Foot-operated switch
Knife switch - Switch with unenclosed conductors
Micro switch - Mechanically activated switch with snap action
Limit switch - Mechanically activated switch to sense limit of motion
Mercury switch - Switch sensing tilt
Centrifugal switch - Switch sensing centrifugal force due to rate of rotation
Relay - Electrically operated switch (mechanical, also see Solid State Relay below)
Reed switch - Magnetically activated switch
Thermostat - Thermally activated switch
Humidistat - Humidity activated switch
Circuit Breaker - Switch opened in response to excessive current: a resettable fuse

Resistors

Pass current in proportion to voltage (ohms law).

Resistor - fixed value
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
Heater - heating element
Resistance wire, Nichrome wire - wire of high-resistance material, often used as heating element
Thermistor - temperature-varied resistor
Humistor - humidity-varied resistor
Varistor, Voltage Dependent Resistor, MOV - Passes current when excessive voltage present

Protection devices

Passive components that protect circuits from excessive currents or voltages

Fuse - Over-current protection, one time use
Circuit Breaker - Resettable fuse in the form of a mechanical switch
PolySwitch or Resettable fuse - Circuit breaker action using solid state device
Ground-fault protection or Residual-current device - Circuit breaker sensitive to mains currents passing to ground
Metal Oxide Varistor, Surge Absorber (MOV), TVS - Over-voltage protection.
Inrush current limiter - Protection against initial Inrush current
Gas Discharge Tube - Protection against high voltage surges
Spark gap - Electrodes with a gap to arc over at a high voltage
Lightning arrester - Spark gap used to protect against lightning strikes

Capacitors

Components that store and release electrical charge. Used for filtering power supply lines, for tuning resonant circuits, and for blocking DC voltages while passing AC signals, among numerous other uses.

Capacitor - fixed capacitance
Capacitor network (array)
Variable capacitor - Adjustable capacitance
Tuning capacitor - Variable capacitor for tuning a radio, oscillator, or tuned circuit
Trimmer capacitor - Small variable capacitor usually for internal adjustments
Varicap diode - AC capacitance varies according to the DC voltage applied.

Magnetic (inductive) devices

Electrical components that use magnetism

Inductor, coil, choke
Variable inductor
Saturable Inductor
Transformer
Magnetic amplifier (toroid)
Ferrite impedances, beads
Motor / Generator
Solenoid
Speaker / Microphone

Networks

Components that use more than one type of passive component

RC network - forms an RC circuit, used in Snubbers
LC Network - forms an LC circuit, used in tuneable transformers and RFI filters

Piezoelectric devices, crystals, resonators

Passive components that use piezoelectric effect

Components that use the effect to generate or filter high frequencies
Crystal - Is a ceramic crystal used to generate precise frequencies (See the Modules class below for complete oscillators)
Ceramic resonator - Is a ceramic crystal used to generate semi-precise frequencies
Ceramic filter - Is a ceramic crystal used to filter a band of frequencies such as in radio receivers
Surface Acoustic Wave (SAW) filters
Components that use the effect as mechanical Transducers.
Ultrasonic motor - Electric motor that uses the piezoelectric effect
For piezo buzzers and microphones, see the Transducer class below

[edit] Power sources

Sources of electrical power

Battery - acid- or alkali-based power supply
Fuel cell - an electrochemical generator
Power supply - usually a mains hook-up
Photo voltaic device - generates electricity from light
Thermo electric generator - generates electricity from temperature gradients
Electrical generator - an electromechanical power source

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.

Audio (see also Piezoelectric devices)
Loudspeaker - Magnetic or piezoelectric device to generate full audio
Buzzer - Magnetic or piezoelectric sounder to generate tones
Position, motion
Linear variable differential transformer (LVDT) - Magnetic - detects linear position
Rotary encoder, Shaft Encoder - Optical, magnetic, resistive or switches - detects absolute or relative angle or rotational speed
Inclinometer - Capacitive - detects angle with respect to gravity
Motion sensor, Vibration sensor
Flow meter - detects flow in liquid or gas
Force, torque
Strain gauge - Piezoelectric or resistive - detects squeezing, stretching, twisting
Accelerometer - Piezoelectric - detects acceleration, gravity
Thermal
Thermocouple, thermopile - Wires that generate a voltage proportional to delta temperature
Thermistor - Resistor whose resistance changes with temperature, up PTC or down NTC
Resistance Temperature Detector (RTD) - Wire whose resistance changes with temperature
Bolometer
Thermal cutoff - Switch that is opened or closed when a set temperature is exceeded
Magnetic field (see also Hall Effect in semiconductors)
Magnetometer, Gauss meter
Humidity
Hygrometer
Electromagnetic, light
Photo resistor - Light dependent resistor (LDR)

Semiconductors

Diodes

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

Standard Diode, Rectifier, Bridge Rectifier
Schottky Diode, Hot Carrier Diode - super fast diode with lower forward voltage drop
Zener Diode - Passes current in reverse direction to provide a constant voltage reference
Transient Voltage Suppression Diode (TVS), Unipolar or Bipolar - used to absorb high-voltage spikes
Varactor, Tuning diode, Varicap, Variable Capacitance Diode - A diode whose AC capacitance varies according to the DC voltage applied.
Light Emitting Diode (LED) - A diode which emits light
LASER Diode - A semiconductor laser
Photodiode - Passes current in proportion to incident light
Avalanche Photodiode Photodiode with internal gain
Solar Cell, photovoltaic cell, PV array or panel, produces power from light
Diode for Alternating Current (DIAC, Trigger Diode, SIDAC) - Often used to trigger an SCR
Constant current Diode
Peltier cooler - A semiconductor heat pump

Transistors

Active components used for amplification.

Bipolar transistors
Bipolar Junction Transistor (BJT, or simply "transistor") - NPN or PNP
Photo transistor - Amplified photodetector
Darlington transistor - NPN or PNP
Photo Darlington - Amplified photodetector
Sziklai pair (Compound transistor, complementary Darlington)
Field effect transistor (FET)
Junction Field Effect Transistor (JFET) - N-CHANNEL or P-CHANNEL
Metal Oxide Semiconductor FET (MOSFET) - N-CHANNEL or P-CHANNEL
MEtal Semiconductor FET (MESFET)
High Electron Mobility Transistor (HEMT)
Thyristors
Silicon Controlled Rectifier (SCR) - Passes current only after triggered by a sufficient control voltage on its gate
TRIode for Alternating Current (TRIAC) - Bidirectional SCR
UniJunction Transistor (UJT)
Programmable UniJunction Transistor (PUT)
Static Induction Transistor/Thyristor (SIT, SITh)
Composite transistors
Insulated Gate Bipolar Transistor (IGBT)

[edit] Integrated circuits

Digital
Analog
Hall effect sensor - Senses a magnetic field
Current sensor - Senses a current through it

Optoelectronic devices

Optoelectronics
Opto-Isolator, Opto-Coupler, Photo-Coupler - Photodiode, BJT, JFET, SCR, TRIAC, Zero-crossing TRIAC, Open collector IC, CMOS IC, Solid State Relay (SSR)
Opto Switch, Opto Interrupter, Optical Switch, Optical Interrupter, Photo switch, Photo Interrupter
LED Display - Seven-segment display, Sixteen-segment display, Dot matrix display

Display technologies

Current:

Filament lamp (indicator lamp)
Vacuum fluorescent display (VFD) (preformed characters, 7 segment, starburst)
Cathode ray tube (CRT) (dot matrix scan (e.g. computer monitor), radial scan (e.g. radar), arbitrary scan (e.g. oscilloscope)) (monochrome & colour)
LCD (preformed characters, dot matrix) (passive, TFT) (monochrome, colour)
Neon (individual, 7 segment display)
LED (individual, 7 segment display, starburst display, dot matrix)
Flap indicator (numeric, preprinted messages)
Plasma display (dot matrix)

Obsolete:

Filament lamp 7 segment display (aka 'minitron')
Nixie Tube
Dekatron (aka glow transfer tube)
Magic eye tube indicator
Penetron (a 2 colour see-through CRT)

Vacuum tubes (Valves)

Based on current conduction through a vacuum (see Vacuum tube)

Diode or Rectifier tube

Amplifying tubes

Triode
Tetrode
Pentode
Hexode
Pentagrid
Octode
Microwave tubes
Klystron
Magnetron
Traveling-wave tube

Optical detectors or emitters

Phototube or Photodiode - tube equivalent of semiconductor photodiode
Photomultiplier tube - Phototube with internal gain
Cathode ray tube (CRT) or Television picture tube
Vacuum fluorescent display (VFD) - Modern non-raster sort of small CRT display
Magic eye tube - Small CRT display used as a tuning meter (obsolete)
X-ray tube - Produces x-rays

Discharge devices

Gas discharge tube

Obsolete:

Mercury arc rectifier
Voltage regulator tube
Nixie tube
Thyratron
Ignitron

Antennas

Antennas transmit or receive radio waves

Elemental dipole
Yagi
Phased array
Loop antenna
Parabolic dish
Log-periodic dipole array
Biconical
Feedhorn

Assemblies, modules

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

Oscillator
Display devices
Liquid crystal display (LCD)
Digital voltmeters
Filter

Prototyping aids

Wire-wrap
Breadboard

Mechanical accessories

Enclosure
Heat sink
Heat sink paste & pads
Fan

Other

Printed circuit boards
Lamp
Waveguide
Memristor

Obsolete:

Carbon amplifier (see Carbon microphones used as amplifiers)
Carbon arc (negative resistance device)
Dynamo (historic rf generator)

Standard symbols
Main article: Electronic symbol

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