SI units for electricity, magnetism, and light

Electricity, magnetism, and light

IEC 80000-6: this section describes the SI units for electricity and magnetism. This includes: electric current (I), electric charge (Q), electric potential (V), capacitance (C), resistance (R), inductance (L), magnetic flux density (B), active power (P), reactive power (Q), apparent power (S)

Electric current, l

ampere, A Usual multiples and sub-multiples: kA, mA, µA

Electric charge, Q

coulomb, C; 1 C = 1 A · s
For storage batteries, the compound unit A · h is used.

Conversion factors

1 A · h = 3,6 kC

Electric potential, V

volt, V; 1 V = 1 W/A = 1 kg · m2/(s3 · A)

Usual multiples and sub-multiples:
kV, mV, µV

The unsystematic name "voltage" should be avoided for electric tension or electric potential difference.

Capacitance, C

farad, F; 1 F = 1 C/V = 1 s4 · A2/(kg · m2)

Usual sub-multiples: µF, nF, pF

Resistance, R

ohm, Ω; 1 Ω = 1 V/A = 1 kg · m2/(s3 · A2)

Usual multiples and sub-multiples:
MΩ, kΩ, mΩ

Inductance, L

henry, H; 1 H = 1 V · s/A = 1 kg · m2/(s2 · A2)

Usual sub-multiples: mH, µH

Magnetic flux density, B

tesla, T; 1 T = V · s/m2 = 1 kg/(s2 · A)

Usual sub-multiples: mT, µT

Active power, P

watt, W; 1 W = 1 J/s = 1 V · A = 1 kg · m/s3

Usual multiples and sub-multiples: MW, kW, mW

Reactive power, Q

volt ampere, V · A; 1 V · A = 1 kg · m/s3

Usual multiples: MV · A, kV · A

IEC has adopted the name var, var (volt-ampere reactive power), for the coherent SI unit volt-ampere for reactive power.

Conversion factors

1 var = 1 V · A

Apparent power, S

volt ampere, V · A; 1 V · A = 1 kg · m/s3

Usual multiples: MV · A, kV · A

Light

ISO 80000-7:  this section describes the SI units for light. This includes: luminous intensity (l), luminous flux (Φ), illuminance (E), light exposure (H)
 

Luminous intensity, I

candela, cd

Luminous flux, Φ

lumen, lm; 1 lm = 1 cd/sr

Illuminance, E

lux, lx; 1 lx = 1 lm/m2 = 1 cd/(sr · m2)

Light exposure, H

lux second, lx · s; 1 lx · s = 1 s · cd/(sr · m2)