NW

nW, or nanowatt, is the SI unit of power equal to one billionth of a watt (10^-9 W). It is used to quantify very small amounts of electrical or optical power in fields such as nanoelectronics, photonics, and ultra-low-power sensing.

Conversion: 1 nW = 10^-9 W = 0.001 µW, since 1 µW = 10^-6 W. Equivalently, 1 nW = 1,000 pW. The watt equals 10^9 nW.

Applications: nanowatts describe power budgets for sleep or idle modes in modern integrated circuits, wireless sensor nodes, energy-harvesting devices, low-light photodetectors, and LED driver systems operating at milli-scale currents. It also appears in measurements of noise power in RF and optical systems.

Measurement and challenges: measuring nanowatt-level power requires high-sensitivity instrumentation and careful noise management. Instruments include nanowatt meters or high-gain transimpedance amplifiers, with techniques to mitigate thermal and shot noise.

See also: pico-watt (pW), micro-watt (µW), milli-watt (mW).