Wikipedia:WikiProject Electronics/Standard symbols

From Wikipedia, the free encyclopedia

Reference should be made to codes and standards. For example, IEC 60027, and Letter Symbols in Electrical Technology.

Here are tables of widely accepted symbols. They are meant to be a guideline: Using the same symbols for the same things in different articles will increase their consistency, making them easier to understand and to improve. If you are looking for the symbol for something that is not on the list, just check whether a particular symbol has been already chosen, and create your own. If anybody will disagree with it, discuss it on the talk page.

It is certainly not an exhaustive list, nor is it in any particular order.

Waves and waveforms[edit]

Symbol Meaning SI Units of Measure
frequency hertz (cycles per second)
angular frequency radians per second
wave number radians per meter
wavelength meters per cycle
period seconds per cycle

Optics and photonics[edit]

Symbol Meaning SI Units of Measure
refractive index dimensionless
speed of light in vacuum meters per second
speed of light in material medium meters per second
frequency hertz (cycles per second)
angular frequency radians per second
wave number radians per meter
wavelength meters per cycle
radius of curvature meters
reflection coefficient dimensionless
absorption coefficient dimensionless
reflectivity dimensionless
transmissivity dimensionless

Electromagnetics[edit]

Symbol Meaning SI Units of Measure
Electric field volts per meter
Magnetic field amperes per meter
Electric displacement coulombs per square meter
Magnetic flux density teslas or
webers per square meter
Electric flux voltmeters
Magnetic flux webers
Polarization density coulombs per square meter
Magnetization amperes per meter
Current density amperes per square meter
Electric permittivity farads per meter
Magnetic permeability henries per meter
conductivity siemens per meter
susceptibility dimensionless
Electric charge coulombs
Electric charge density coulombs per cubic meter
Electric potential volts
Magnetic scalar potential amperes
Magnetic vector potential webers per meter

R} Resistance of " R"

Electrical circuits[edit]

Symbol Meaning SI Units of Measure
Susceptance siemens
Capacitance farad
Conductance siemens
Inductance henry
Current ampere
Alternating Current ampere
Power Watt
Reactive Power Volt-Ampere Reactive
Resistance ohm
Apparent Power Volt-Ampere
Voltage volt
Alternating Voltage volt
Reactance ohm
Admittance siemens
Impedance ohm

Signals and systems[edit]

Symbol Meaning SI Units of Measure
time seconds
the imaginary unit dimensionless
base of the natural logarithm
2.71828...
dimensionless
ratio of the circumference
to the diameter of a circle
3.1415927...
dimensionless
time constant seconds
exponential decay constant
or attenuation coefficient
nepers per second (1/second)
instantaneous angle in argument of sinusoid radians (dimensionless)
phase angle radians (dimensionless)
quality factor dimensionless
Bandwidth hertz
damping factor dimensionless
Correlation between x and y dimensionless
Standard deviation of x same units as x
Mean value of x same units as x
Expected value of the random variable X same units as X
nth moment of a function nth power of the domain's units
Autocorrelation of random process X(t) watts
Power spectral density of random process X(t) watts per hertz