The statohm (symbol: statΩ) is the unit of

electrical resistance The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual paral ...

in the electrostatic system of units which was part of the CGS system of units based upon the centimetre, gram and second. The static units in that system are related to the corresponding electromagnetic units by a factor of the

speed of light The speed of light in vacuum, commonly denoted , is a universal physical constant exactly equal to ). It is exact because, by international agreement, a metre is defined as the length of the path travelled by light in vacuum during a time i ...

. Those units are known as absolute units, and so the counterpart of the statohm is the

abohm The abohm is the derived unit of electrical resistance in the emu-cgs ''(centimeter-gram-second)'' system of units (emu stands for "electromagnetic units"). One abohm corresponds to 10−9 ohms in the SI system of units, which is a nanooh ...

(abΩ), and their proportions are: 1 statΩ ≘ ''c''² abΩ ≈ abΩ where ''c'' is the speed of light in centimetres per second. These units are not common now. The

SI unit The International System of Units, internationally known by the abbreviation SI (from French ), is the modern form of the metric system and the world's most widely used system of units of measurement, system of measurement. It is the only system ...

of resistance is the

ohm Ohm (symbol Ω) is a unit of electrical resistance named after Georg Ohm. Ohm or OHM may also refer to: People * Georg Ohm (1789–1854), German physicist and namesake of the term ''ohm'' * Germán Ohm (born 1936), Mexican boxer * Jörg Ohm (1 ...

(Ω). The statohm is nearly a

trillion ''Trillion'' is a number with two distinct definitions: *1,000,000,000,000, i.e. one million 1,000,000, million, or (ten to the twelfth Exponentiation, power), as defined on the long and short scales, short scale. This is now the meaning in bot ...

times larger than the ohm and is the largest unit of resistance ever used in any measurement system. The statohm as a practical unit is as unusably large as the abohm is unusably small. 1 statΩ ≘ ''c''² × Ω ≈ Ω The sign ≘ denotes 'correspondence' between quantities. Equality does not apply, since the systems of quantities underlying the two systems of units are mutually incompatible.

References

{{CGS units Units of electrical resistance Centimetre–gram–second system of units