Difference between voltage and current?

Voltage is electrical potential, measure in derived units of volts, which is joules per coulomb. Current is electrical flow, measured in derived units of amperes, which is coulombs per second. Stated in other terms, voltage is energy per charge, while current is charge per time. That makes power, or watts, equal to energy per time, and that is joules per second.

If you think of the water system analogy, volts is sort of similar to pounds per square inch (though not completely so), while amperes is similar to gallons per minute.


Voltage is synonymous with 'potential difference' -not potential- measured in volts. Current is the flow of electrical charge, measured in amperes. The volt is an SI derived unit, wheras an ampere is an SI base unit.