nanowatt

Nanowatt (nW) is the SI unit of power equal to 10^-9 watts. The nano- prefix denotes one billionth, so 1 nW is one billionth of a watt. The symbol for the unit is nW.

In terms of other prefixes, 1 nW equals 0.001 μW and 1000 pW. This places nanowatts in the very small end of the power scale, useful for describing ultra-low-power systems and nanoscale devices where even tiny energy losses matter.

Applications and context: Nanowatts are used to quantify power budgets in ultra-low-power electronics, sensors, and wireless transceivers, particularly in nanoscale or energy-constrained environments. They are relevant for devices with duty-cycled operation, energy harvesting, or batteryless designs, such as certain wireless sensor networks, biomedical implants, and MEMS. Designers analyze average power consumption over time, often expressing it in nanowatts or nanowatt-hours per cycle.

Measurement and considerations: Measuring power in the nanowatt range requires specialized, low-noise instrumentation, such as dedicated low-power meters or calibrated calorimetric methods. Real-world measurements must account for leakage, temperature effects, and transient behaviors. Understanding nanowatt-scale performance is essential for assessing the feasibility and lifetime of ultra-low-power systems.

See also: related units include the microwatt and picowatt.