abvolt
A unit of electrical potential equal to one hundred millionth of a volt (10⁻⁸ volts), used in the centimeter-gram-second system of units.
abvolt: a CGS unit of tiny electrical pressure
An abvolt is a unit of electrical potential difference in the centimeter-gram-second (CGS) system of units, equal to 10−8 volts or 0.00000001 V. It represents an extraordinarily small voltage: one ten-millionth of a volt. The unit was used primarily in laboratories and theoretical physics work during the late nineteenth and early twentieth centuries, when the CGS system dominated European and American scientific practice before the adoption of SI units.
The name itself reveals its structure. The prefix ab comes from abampere, the CGS unit of electrical current. Just as an abampere relates to the practical ampere through the CGS electromagnetic system, the abvolt derives its voltage definition from the relationship between current and resistance in that same framework. In CGS-emu (electromagnetic units), 1 abvolt is the potential difference across a 1 abohm resistance when 1 abampere flows through it.
Why it matters so little today
Modern industrial and scientific work uses the SI system exclusively. The abvolt has vanished from contemporary engineering datasheets, equipment specifications, and laboratory practice. Anyone encountering the term now does so only in historical technical documents, older physics texts, or when decoding legacy measurement records. SI units (volt, millivolt, microvolt) are far more intuitive and universally standardized.
The CGS system produced a confusing hierarchy of units where electromagnetic quantities could be defined in two incompatible ways (electrostatic units and electromagnetic units). The abvolt belonged to the emu branch, which made cross-system calculations cumbersome. When SI unified electrical measurement under a single coherent framework in the mid-twentieth century, practical workers had little reason to preserve abvolts in their vocabulary.
If you encounter an abvolt in a technical document, convert immediately: divide by 108 to get volts, or multiply by 100 to get nanovolts. The conversion is straightforward, but the unit itself belongs to industrial history rather than current practice.