Basic units in the International System of Units (Système International d´Unités) or SI, adopted in the Conference Générale des Poids et Measures in 1960. These units define twenty-two named units and many more derived units. The system also includes a set of twenty prefixes to the unit names and unit symbols used with multiples and fractions of the units.
They are:
Table 1
| Quantity | Unit | Symbol |
| Length | Meter | m |
| Mass | Kilogram | Kg |
| Time | second | s |
| electric current | ampere | A |
| Temperature | Kelvin | K |
| luminous intensity | candela | cd |
| Amount of substance | mole | Mol |
Other basic electric units are:
Table 2
| Unit | Symbol | Quantity | Additional Information |
| Ampere | A | Electric current | Ampere-hour |
| R | Ah | Electric energy | - |
| Ampere-turn | At | Magnetic-field intensity | Is a CGS unit – The Oesterd is preferred |
| Bel | B | Audio Power level | - |
| Corlomb | C | Electric charge | - |
| Cycle per second | c/s | Frequency | Not used – the Hertz (Hz) is accepted for this unit |
| Decibel | dB | Audio Power level | - |
| Decibel – refered to 1 mW | dBm | Audio Power level | - |
| Farad | F | Capacitance | - |
| Gauss | G | Magnetic induction | Is a CGS unit. SI adopted the Tesla (T). |
| Gilbert | Gb | Magnetomotive force | Is a CGS unit. The SI unit is the amperes/turn or ampere |
| Henry | H | Indutance | - |
| Hertz | Hz | Frequency | - |
| Horsepower | hp | Power | It isn´t a SI unit, but is used in many practical applications. The unit used in SI is the watt. |
| Maxwell | Mx | Magnetic flux | This is a CGS electromagnetic unit. SI adopted the Weber. |
| Mho | mho | Electric Condutance | The EC adopted the Siemens (S) as unit of condutance |
| Oersted | Os | Magnetic Field Intensity | This is a electromagnetic CGS unit of magnetic field strenggth. SI adopted the amperes per meter (A/m) |
| Ohm | ? | Electric resistance | - |
| Revolutions per minute | rpm or r/m | rpm is used but not recommended | |
| Siemens | S | Electric conductance | mho can be found in old publications |
| Volt | V | Electric Potential | - |
| Watt | W | Electric Power | - |
| Watt-hour | Wh | Electric Energy | - |
| Weber | Wb | Magnetic Flux | 1 Wb = 1 V.s |
