A square micrometer (often abbreviated as μm²) is a unit of area in the International System of Units (SI). It represents a square with sides that each measure 1 micrometer (μm) in length.
One square micrometer is equal to 1.0 × 10^-12 square meters (m²) because there are 1,000,000 micrometers in a meter, and when you square that length, you get 1.0 × 10^-12 square meters.
To visualize the size of a square micrometer, you can think of an extremely tiny square with sides that are each 1 micrometer long. It is an exceedingly small unit of area and is often used in scientific and technical contexts when dealing with very small scales, such as in microscopy and nanotechnology.
A circular mil (often abbreviated as cmil or kcmil) is a unit of area used primarily in the United States for measuring the cross-sectional area of a round wire or cable. It is a convenient unit for specifying the size of electrical conductors.
One circular mil is equal to the area of a circle with a diameter of one mil (1/1000th of an inch) or approximately 0.000000506707 square inches (in²). In metric units, one circular mil is approximately equal to 0.000001273 square millimeters (mm²).
Circular mils are commonly used in the American Wire Gauge (AWG) system to specify wire sizes. The AWG system assigns a unique number to each wire size, and this number is related to the wire's cross-sectional area in circular mils. For example, a larger AWG number corresponds to a smaller wire size with fewer circular mils, while a smaller AWG number corresponds to a larger wire size with more circular mils. This system allows for easy reference and selection of wire sizes for various electrical applications.