Electronic component introduction

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 and elements.

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 amplifierradio 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 circuitshybrid integrated circuits, or thick film devices.


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 connectionsMost 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. In contrast, active components (with more than two terminals) generally lack that property.

Active components



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.


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

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.

Programmable devices

  • Programmable logic device
  • Field-programmable gate array (FPGA)
  • Complex programmable logic device (CPLD)
  • Field-programmable analog array (FPAA)

Optoelectronic devices

Display technologies



  • Incandescent filament 7 segment display (aka ‘Numitron’)
  • Nixie tube
  • Dekatron (aka glow transfer tube)
  • Magic eye tube indicator
  • Penetron (a 2 colour see-through CRT)
  • Vacuum tubes (valves)
  • A vacuum tube is based on current conduction through a vacuum.
  • Discharge devices
  • Gas discharge tube
  • Ignitron
  • Thyratron
  • Obsolete:
  • Mercury arc rectifier
  • Voltage regulator tube
  • Nixie tube
  • Power sources
  • Sources of electrical power:
  • Battery – acid- or alkali-based power supply.
  • Fuel cell – an electrochemical generator
  • Power supply – usually a main hook-up
  • Photovoltaic device – generates electricity from light
  • Thermoelectric generator – generates electricity from temperature gradients
  • Electrical generator – an electromechanical power source
  • Piezoelectric generator - generates electricity from mechanical strain
  • Van de Graaff generator - generates electricity from friction
  • 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


  • Pass current in proportion to voltage and oppose current.
  • 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
  • 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.
  • Humistor – humidity-varied resistor
  • Photoresistor
  • Memristor
  • VaristorVoltage-dependent resistorMOV – Passes current when excessive voltage is present
  • Resistance wireNichrome wire – wire of high-resistance material, often used as a heating element
  • Heater – heating element


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.

1. Integrated capacitors

(1) MIS capacitor

(2) Trench capacitor

2. Fixed capacitors

(1) Ceramic capacitor

(2) Film capacitor

(3) Electrolytic capacitor

① Aluminum electrolytic capacitor

② Tantalum electrolytic capacitor

③ Niobium electrolytic capacitor (Columbium capacitor)

④ Polymer capacitorOS-CON

(4) Supercapacitor (Electric double-layer capacitor)

① Nanoionic supercapacitor

② Lithium-ion capacitor

(5) Mica capacitor

(6) Vacuum capacitor

3. Variable capacitor – adjustable capacitance

(1) Tuning capacitor – variable capacitor for tuning a radio, oscillator, or tuned circuit

(2) Trimmer capacitor – small variable capacitor for seldom or rare adjustments of LC-circuits

(3) Vacuum variable capacitor

4. Capacitors for special applications

(1) Power capacitor

(2) Safety capacitor

(3) Filter capacitor

(4) Light-emitting capacitor (LEC)

(5) Motor capacitor

(6) Photoflash capacitor

(7) Reservoir capacitor / Bulk capacitor

(8) Coupling capacitor

(9) Decoupling capacitor / Buffer capacitor

(10) Bypass capacitor

(11) Pull capacitor / Padding capacitor

(12) Backup capacitor

(13) Switched capacitor

(14) Feedthrough capacitor

5. Capacitor network (array)

  • 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
  • Electical components that use magnetism in the storage and release of electrical charge through current:
  • Inductor, coil, choke
  • Variable inductor
  • Saturable inductor
  • Transformer
  • Magnetic amplifier (toroid)
  • Ferrite impedances, beads
  • Motor / Generator
  • Solenoid
  • Loudspeaker and microphone
  • 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:
  • RC network - forms an RC circuit, used in snubbers
  • LC network - forms an LC circuit, used in tunable transformers and RFI filters.
  • 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.

  •  Audio

1. Loudspeaker – Electromagnetic or piezoelectric device to generate full audio

2. Buzzer – Electromagnetic or piezoelectric sounder to generate tones

  • Position, motion

1. Linear variable differential transformer (LVDT) – Magnetic – detects linear position

2. Rotary encoder, Shaft Encoder – Optical, magnetic, resistive or switches – detects absolute or relative angle or rotational speed

3. Inclinometer – Capacitive – detects angle with respect to gravity

4. Motion sensor, Vibration sensor

5. Flow meter – detects flow in liquid or gas

  • Force, torque

1. Strain gauge – Piezoelectric or resistive – detects squeezing, stretching, twisting

2. Accelerometer – Piezoelectric – detects acceleration, gravity

  • Thermal

1. Thermocouplethermopile – Wires that generate a voltage proportional to delta temperature

2. Thermistor – Resistor whose resistance changes with temperature, up PTC or down NTC

3. Resistance Temperature Detector (RTD) – Wire whose resistance changes with temperature

4. Bolometer – Device for measuring the power of incident electromagnetic radiation

5. Thermal cutoff – Switch that is opened or closed when a set temperature is exceeded

Magnetic field (see also Hall Effect in semiconductors)

1. Magnetometer, Gauss meter

  • Humidity

1. Hygrometer

  • Electromagnetic, light

1. Photo resistor – Light dependent resistor (LDR)


Antennas transmit or recieve 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

1. Liquid crystal display (LCD)

2. Digital voltmeters

  • Filter

Prototyping aids

  • Wire-wrap
  • Breadboard


Piezoelectric devices, crystals, resonators

Passive components that use piezoelectric effect:

  • Components that use the effect to generate or filter high frequencies

1. Crystal – a ceramic crystal used to generate precise frequencies (See the Modules class below for complete oscillators)

2. Ceramic resonator – Is a ceramic crystal used to generate semi-precise frequencies

3. Ceramic filter – Is a ceramic crystal used to filter a band of frequencies such as in radio receivers

4. surface acoustic wave (SAW) filters

  • Components that use the effect as mechanical transducers.

1. Ultrasonic motor – Electric motor that uses the piezoelectric effects

2. Piezo buzzers and microphones

Microelectromechanical systems

  • Accelerometer
  • Digital micromirror device

Terminals and connectors

Devices to make electrical connection

  • Terminal
  • Connector

1. Socket

2. Screw terminal, terminal blocks

3. Pin header

Cable assemblies

Electrical cables with connectors or terminals at their ends

  • Power cord
  • Patch cord
  • Test lead


Components that can pass current(“closed”) or break the current (“open”):

  • Switch – Manually operated switch

1. Electrical description: SPST, SPDT, DPST, DPDT, NPNT (general)

2. Technology: slide switches, toggle switches, rocker switches, rotary switches, pushbutton switches

Protection devices

Passive components that protect circuits from excessive currents or voltages:

Mechanical accessories

  • Enclosure (electrical)
  • Heat sink
  • Fan


  • Printed circuit boards
  • Lamp
  • Waveguide


  • Carbon amplifier
  • Carbon arc (negative resistance device)
  • Dynamo (historic rf generator)
  • Coherer
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