Amperage is electric current expressed in amperes (A), commonly called amps. One ampere corresponds to one coulomb of charge passing a point per second.
Reading fixture specifications
Distinguish operating current, a maximum input-current rating and startup inrush. Also identify whether the figure is for AC input, DC input or battery charging. A listed maximum is not necessarily the current drawn at every dimming level and supply voltage.
Practical example
For an illustrative steady DC load drawing 120 W at its input, 24 V corresponds to 5 A. At an AC input, real power divided by voltage alone is insufficient unless power factor is effectively one; RMS current is P ÷ (V × PF) for the single-phase case.
Current and supply capacity
A battery’s amp-hour capacity describes stored charge and is different from its permitted discharge current. A supply being labelled with a large current capacity does not force that current through a compatible regulated load. Confirm the fixture, supply, cable and connector ratings together; a calculation is not approval of a circuit arrangement.
Equipment examples
The Aputure Nova P600c can use mains or a specified DC supply. Keep the current requirements for those inputs separate when reading its power data.
Related terms
Voltage · Watt · Power Factor · Inrush Current · DC Power
References
Fluke: electric current · NIST: SI base and derived units · Vertiv: power definitions and terms