Electrical Units

Electrical & electronic units of electric current, voltage, power, resistance, capacitance, inductance, electric charge, electric field, magnetic flux, frequency:

Electrical & electronic units table

Unit Name Unit Symbol Quantity
Ampere (amp) A Electric current (I)
Volt V Voltage (V, E)

Electromotive force (E)

Potential difference (Δφ)

Ohm Ω Resistance (R)
Watt W Electric power (P)
Decibel-milliwatt dBm Electric power (P)
Decibel-Watt dBW Electric power (P)
Volt-Ampere-Reactive var Reactive power (Q)
Volt-Ampere VA Apparent power (S)
Farad F Capacitance (C)
Henry H Inductance (L)
siemens / mho S Conductance (G)

Admittance (Y)

Coulomb C Electric charge (Q)
Ampere-hour Ah Electric charge (Q)
Joule J Energy (E)
Kilowatt-hour kWh Energy (E)
Electron-volt eV Energy (E)
Ohm-meter Ω∙m Resistivity (ρ)
siemens per meter S/m Conductivity (σ)
Volts per meter V/m Electric field (E)
Newtons per coulomb N/C Electric field (E)
Volt-meter V⋅m Electric flux (Φe)
Tesla T Magnetic field (B)
Gauss G Magnetic field (B)
Weber Wb Magnetic flux (Φm)
Hertz Hz Frequency (f)
Seconds s Time (t)
Meter / metre m Length (l)
Square-meter m2 Area (A)
Decibel dB  
Parts per million ppm  

Units prefix table







pico p 10-12 1pF = 10-12F
nano n 10-9 1nF = 10-9F
micro μ 10-6 1μA = 10-6A
milli m 10-3 1mA = 10-3A
kilo k 10 3 1kΩ = 1000Ω
mega M 10 6 1MHz = 106Hz
giga G 10 9 1GHz = 109Hz


Electrical units definitions

Volt (V)

Volt is the electrical unit of voltage.

One volt is the energy of 1 joule that is consumed when electric charge of 1 coulomb flows in the circuit.

1V = 1J / 1C

Ampere (A)

Ampere is the electrical unit of electrical current. It measures the amount of electrical charge that flows in an electrical circuit per 1 second.

1A = 1C / 1s

Ohm (Ω)

Ohm is the electrical unit of resistance.

1Ω = 1V / 1A

Watt (W)

Watt is the electrical unit of electric power. It measures the rate of consumed energy.

1W = 1J / 1s

1W = 1V ⋅ 1A

Decibel-milliwatt (dBm)

Decibel-milliwatt or dBm is a unit of electric power, measured with logarithmic scale referenced to 1mW.

10dBm = 10 ⋅ log10(10mW / 1mW)

Decibel-Watt (dBW)

Decibel-watt or dBW is a unit of electric power, measured with logarithmic scale referenced to 1W.

10dBW = 10 ⋅ log10(10W / 1W)

Farad (F)

Farad is the unit of capacitance. It represents the amount of electric charge in coulombs that is stored per 1 volt.

1F = 1C / 1V

Henry (H)

Henry is the unit of inductance.

1H = 1Wb / 1A

siemens (S)

siemens is the unit of conductance, which is the opposite of resistance.

1S = 1 / 1Ω

Coulomb (C)

Coulomb is the unit of electric charge.

1C = 6.238792×1018 electron charges

Ampere-hour (Ah)

Ampere-hour is a unit of electric charge.

One ampere-hour is the electric charge that flow in electrical circuit, when a current of 1 ampere is applied for 1 hour.

1Ah = 1A ⋅ 1hour

One ampere-hour is equal to 3600 coulombs.

1Ah = 3600C

Tesla (T)

Tesla is the unit of magnetic field.

1T = 1Wb / 1m2

Weber (Wb)

Weber is the unit of magnetic flux.

1Wb = 1V ⋅ 1s

Joule (J)

Joule is the unit of energy.

1J = 1 kg ⋅ 1(m / s)2

Kilowatt-hour (kWh)

Kilowatt-hour is a unit of energy.

1kWh = 1kW ⋅ 1h = 1000W ⋅ 1h

Kilovolt-amps (kVA)

Kilovolt-amps is a unit of power.

1kVA = 1kV ⋅ 1A = 1000 ⋅ 1V ⋅ 1A

Hertz (Hz)

Hertz is the unit of frequency. It measures the number of cycles per second.

1 Hz = 1 cycles / s


See also

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