UNIT 1
UNIT SI
There are seven, dimensionally independent, base SI-units and two supplementary units. All other
units can be derived from the base ones. Below, you can find the list of the base SI units as well as
the list of the derived units.
SI base units list
Unit
Meter (metre)
Kilogram
Second
Ampere
Kelvin
Mole
Candela
Pascal
Joule
Watt
Newton
Quantity
Length
Mass
Time
Electric current
Thermodynamic temperature
Amount of substance
Luminous intensity
SI Supplementary Units
rad
Plane angle (2D angle)
sr
Solid angle (3D angle)
SI Derived Units
Symbol
In SI Units
Quantity
Mechanics
Pa
kg·m-1·s-2
Pressure,Stress
J
kg·m2·s-2
Energy,Work,Heat
2
-3
W
kg·m ·s
Power
N
kg·m·s-2
Force,Weight
Tesla
Henry
Coulomb
Volt
Farad
Siemens
Weber
Ohm
T
H
C
V
F
S
Wb
Ω
Electromagnetism
kg·s-2·A-1
Magnetic Field
kg·m2·s-2·A-2
Inductance
A·s
Electric Charge
kg·m2·s-3·A-1
Voltage
kg-1·m-2·s4·A2
Electric Capacitance
kg-1·m-2·s3·A2
Electrical Conductance
kg·m2·s-2·A-1
Magnetic Flux
2
-3
-3
kg·m ·s ·A
Electric Resistance
Lux
Lumen
lx
lm
cd·sr·m-2
cd·sr
Becquerel
Gray
Sievert
Bq
Gy
Sv
Radioactivity
s-1
Radioactivity
m2·s-1
Absorbed Dose
m2·s-1
Equivalent Dose
Hertz
Katal
Hz
kat
s-1
mol·s-1
Radian
Steradian
Unit
Symbol
m
kg
s
A
K
mol
cd
Optics
Illuminance
Luminous Flux
Other
Frequency
Catalytic Activity
UNIT 1
Electrical & electronic units table
Unit
Symbol
Unit Name
Quantity
Ampere (amp)
A
Electric current (I)
Volt
V
Voltage (V, E)
Ohm
Ω
Resistance (R)
Watt
Electric power (P)
dBm
W
dBm
Volt-AmpereReactive
VAR
Reactive power (Q)
Volt-Ampere
VA
F
H
Apparent power (S)
Farad
Henry
S
siemens / mho
Electromotive force (E) / Electric potential (φ)
Impedance (Z)
Electric power (P)
Capacitance (C)
Inductance (L)
Conductance (G)
Admittance (Y)
Electric charge (Q)
Volts per meter
C
A·h
J
kWh
Ω∙m
S/m
V/m
Newtons per
coulomb
N/C
Electric field (E)
Volt-meters
V·m
T
G
Wb
Hz
s
m
m2
Electric flux (Φe)
Coulomb
Ampere-hour
Joule
Kilowatt-hour
Ohm-meter
siemens per meter
Tesla
Gauss
Weber
Hertz
Seconds
Meter / metre
Square-meter
Electric charge (Q)
Energy (E)
Energy (E)
Resistivity (ρ)
Conductivity (σ)
Electric field (E)
Magnetic field (B)
Magnetic field (B)
Magnetic flux (Φm)
Frequency (f)
Time (t)
Length (l)
Area (A)
Units prefix table
Prefix
pico
nano
micro
milli
kilo
mega
giga
Prefix
Prefix
Symbol
factor
p
n
μ
m
K
M
G
10-12
10-9
10-6
10-3
10 3
10 6
10 9
Example
1pF = 10-12F
1nF = 10-9F
1μA = 10-6A
1mA = 10-3A
1KΩ = 1000Ω
1MHz = 106Hz
1GHz = 109Hz
UNIT 1
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
dBm
dBm is a unit of electric power, measured in dB-milliwatts.
1dBm = 10 · log10(1.2589mW / 1mW)
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
UNIT 1
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 = 1000W · 1h
Hertz (Hz)
Hertz is the unit of frequency. It measures the number of cycles per second.
1 Hz = 1 cycles / s
Farad (F)
Farad is the unit of capacitance. It is named after Michael Faraday.
The farad measures how much electric charge is accumulated on the capacitor.
1 farad is the capacitance of a capacitor that has charge of 1 coulomb when applied voltage drop of 1 volt.
1F = 1C / 1V