U.S. Department of Commerce NBS Misc. Publ. 268"

National Bureau of Standards Issued June 1%5

Washington, D.C. 20234 Price 10?; S6.2o per 100 ELECTRICAL ENGINEERING UNITS AND CONSTANTS

As adopted by NBS 1 Symbols and Units Quantity

charge

current

voltage, potential difference electromotive force resistance conductance

reactance susceptance impedance

admittance

capacitance inductance

energy, work power

resistivity conductivity

electric displacement

Symbol Q

Ive

Rcx

B

z

)c

Lw

p

p

Unit Symbol

coulomb ampere

volt

onm

mhu

(Siemens) ohm mhu

ohm

mho

farad henry

joule

mh<i

watt

0

A/V, ( (Si n

A/V, or mho n

A/V, or mho

FH

JwDm

mho/in C/'nr

ohm-meter mho per meter D coulomb per sq meter E volt per meter

€ farad per meter

€ r (numeric!

<t> weber ampere (ampere

turn*

•ft ampere per A/W b weber & weber per Wb/A

ampere |uverl Reprinted from NBS Technical New* Bulletin. May 1965.

nts. I S. Government Printing nre 10<: S6.2.S per 100

electric field strength

permittivity labsolute

relative permittivity magnetic flux magnetomotive force

reluctance

permeance

Y/m

F/m Wh

A

•For sale bv the Superintendent of D> Office. Washington. D.C. 20402

ELECTRICAL ENGINEERING UNITS AND CONSTANTS

Symbols and Units — Continued Quantity Symbol Unit Si m bol magnetic flux density B tesla T

magnetic field strength 11 ampere per A/m

meter

permeability (absolute) henry per meter H/m

relative permeability (numeric!

length / meter m

mass m kilogram kg

time t second s frequency f hertz Hz

angular frequency- radian per rad/s second

force F newton N

pressure P newton per sq. N/m1 meter

temperature (absolute) T degree Kelvin °K

temperature t degree Celsius °C

(International)

Physical Constanis- Constant

electronic charge speed of light in vacuum

permittivity of vacuum, electric constant

permeability of vacuum, magnetic constant Planck constant Bolt/mann constant Faraday constant

proton gyro magnetic ratio standard gravitational acceleration normal atmospheric pressure

Symbol Rounded Value

1.602 x 10- |9 C

r 2.9979 x 10»m/s

6>, r,. 8.8542 X 10- |J F/m

4ttX 10"; H/mt

h 6.63 x lO-^J-s

1, 1.38X10-»J/°K F 9.649 x WC/mol y 2.6752 x 10"rad/sT

e"n 9.80665 m/s2 t

atm 101 325 N/mJ +

(t denned value)

2 A general list of physical constants giving more exact values

is contained in NBS Misc. Publ. 253, for sale by the Superintendent of Documents. U.S. Government Printing Office. Washington. D.C, 20402 (Sjf each: $2.50 per lOOl.
Washington, D.C. 20234

| «"ise d AuKus, 1976

Un«h and Symbols

Quantity

current charge

v°llage, poieniiaJ

e(iergy, power

resistance inductance

resistivity conductivity reactance Miscepiance mpedance

admittance

capacitance inductance

electric flux density

electric held strength

Permittivity

relative permute,,. magnetic flux magnetic flux dens,t v magnetic held strength Permeability

relative permeihilny magnetomotive force reluctance Permeance

length mass

time

force pressure frequency

angular frequency

plane angle

solid angle

Svmhol

IQ

y

up

RC

Unit ampere

coulomb

volt joule

wail "dm

Siemens ohm-meter

Siemens per meter ohm

Siemens ohm

Siemens

farad henry coulomb per square meter

v"ll per meter

farad per meter

'Pure number)

weber

tesla ampere per meter "Wry Per meter

'Pure number) ampere

ampere per weber

weber per ampere

meter

kilogram second newton

pascal

hertz radian per second

radian

steradian

Symbol AC

V

Jan

s

fi m

S/rn

fi S

fi S

FH

C/m*

Uniti and Symbob — Continued

Quantity Symbol Unit Symbol

thermodynamic T kelvin K

temperature

Celsius temperature t degree Celsius °C amount of substance " mole mol

luminous intensity / candela cd

Priyticol Comtontt 1

Constant Symbol Rounded Value

elementary charge 1.6022 X 10-'" C

speed of light in vacuum 2.9979246 x 10« m/s

Co 8.854188 x 10-" F/m

magnetic constant 4irx 10 ' H/mt

Planck constant h 6.626 x 10 * J s Boltzmann constant k 1.381 x 10 " J/K Faraday constant F 9.648 x 10< C/mol

proton gyromagnetic ratio Te 2.6752 x 10" rad/l~ T) standard acceleration of free fall Kb 9.81)665 m/s't

standard atmosphere aim 101325 Pat

it defined value)

1 See Fundamental Physical Constants, NBS Special Pubbcation 398. AuguST 1974 (Pocket Card), Price 25c; S6.35 per 1(H).

Decimal Prefix** Factor Prefix Symbol Factor Prefix Symbol

10" exa E 10-' deci d 10" peta P 10-' centi 10" tera T 10-> milli 10» giga C 10" At

10' mega M 10"

III

1 kilo k 10-" pico 1' 10* hecto h 10-" femto f

II dcka da 10-'» atto

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402

Price 35 cents. Stock Number 003-003-01665-:)

ft GPO: 1977 O—219-080