Mw

The milliwatt (symbol mW) is a unit of power in the International System of Units (SI). It equals one thousandth of a watt (10^-3 W). The prefix milli- denotes 10^-3. Because electronic signals and optical outputs often involve small powers, milliwatts are a common unit in engineering and science.

In practical terms, 1 mW is 0.001 W; multiples scale linearly (e.g., 10 mW = 0.01 W, 100 mW = 0.1 W). The term is widely used in contexts such as laser and LED output, RF transmitter power, and photodetector inputs.

Optical and laser applications often quote power in mW. For example, many consumer laser pointers emit a few milliwatts at the aperture, while fiber-optic and laser systems may require tens to hundreds of milliwatts for effective transmission. Safety standards for laser exposure commonly reference power levels in mW or dBm.

The decibel-milliwatt (dBm) is a logarithmic unit for expressing power relative to 1 mW. The relationship is dBm = 10 log10(P(mW)). Consequently, 1 mW corresponds to 0 dBm, 10 mW to 10 dBm, and 0.1 mW to -10 dBm. This helps compare very different power levels across RF, microwave, and optical systems.

Summary: mW is a convenient unit for describing small powers in electronics and photonics, bridging practical measurements and logarithmic scales used in specifications and receiver budgets.