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