15W

15W denotes a power rating of 15 watts, used to describe the rate of energy transfer or consumption in devices and systems.

The watt (W) is the SI unit of power, defined as one joule per second. It is named after Scottish engineer James Watt.

In consumer electronics, 15W commonly appears on lighting and charging devices. LED bulbs and fixtures may carry a 15W rating to indicate energy use; power adapters and wireless chargers may specify 15W as their output rating. Real performance depends on efficiency, voltage, and design.

Power is calculated as P = V × I; thus a 15W device at 5 volts draws 3 A, while at 12 volts it would draw about 1.25 A, neglecting conversion losses.

The notation can also appear as part of model numbers or product names, where 15W is not necessarily a direct reflection of current power usage or output.