Hartley (unit)

The hartley (symbol Hart) is a unit of information defined by International Standard IEC 80000-13 of the International Electrotechnical Commission. One hartley is the information content of an event if the probability of that event occurring is 1/10.^[1] It is therefore equal to the information is contained in one decimal digit (or dit), assuming a priori equiprobability of each possible value.

1 Hart ≈ 3.322 Sh ≈ 2.303 nat.

Though not an SI unit, the hartley is part of the International System of Quantities. It is named after Ralph Hartley. It supersedes the ban, an earlier name for the same unit.

See also

• bit

References