International Standards and Conformity Assessment for all electrical, electronic and related technologies
Main title

SI Zone

International System of Units

 

Electricity and magnetism

This section describing the SI units for the electricity and magnetism is covered in IEC 80000-6.

 

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