siemens

siemens — noun

1. the scientific unit used to measure how easily electricity can move through an o

1.nounC1
Definition

the scientific unit used to measure how easily electricity can move through an object or substance. One siemens equals the rate of flow of one ampere when one volt of electrical pressure is applied.

Example

Devika checked the cable's rating; its conductance was 50 siemens.

collocation: measured in siemens

The datasheet listed the output conductance as 0.2 siemens.

invariant plural: 0.2 siemens

Common collocations
  • measured in siemens
  • siemens per metre
  • conductivity in siemens
Synonyms
  • mho

    older, non-SI name; the word 'ohm' spelled backwards

Usage Note

The plural form is the same as the singular: '5 siemens' (not '5 siemenses'). The symbol is an uppercase S — for example, '10 mS' means 10 millisiemens. The unit is the reciprocal of the ohm: conductance (in siemens) = 1 ÷ resistance (in ohms).

Common Mistakes

The resistor has a siemens of 100.
The resistor has a conductance of 100 siemens.
siemens is a unit of measurement, not the name of the property being measured.
Idioms

Sir William Siemens

idiom

a biographical entry for the German-born British engineer and inventor (1823–1883) after whom the Siemens family industrial company is named. The SI unit of conductance (siemens) was actually named after his older brother, Ernst Werner von Siemens.

Sir William Siemens developed the regenerative furnace, which saved large amounts of fuel in steel-making.

Word family

Synonym discussion

Sense: noun/1

Siemens and mho both measure electrical conductance — the ease with which electricity flows through a material. One siemens equals one mho exactly; they are different names for the same SI unit. Mho (ohm spelled backwards) is the older term and rarely appears outside historical textbooks. Ohm, by contrast, measures resistance — the opposite of conductance. A material with high resistance in ohms has low conductance in siemens, and the two values are mathematical reciprocals: siemens = 1 ÷ ohms. If a wire has 10 ohms of resistance, its conductance is 0.1 siemens (or 0.1 mho).

siemens ↗mhoohm

Common collocations

Nouns

  • conductance (in siemens)
  • value (in siemens)
  • conductivity (in siemens per metre)

Phrases

  • siemens per metre

Prepositions

  • in siemens
  • of siemens

Etymology

GermanEnglish

The unit is named after the German inventor and industrialist Ernst Werner von Siemens (1816–1892), who made major contributions to electrical engineering and telegraphy. The surname itself comes from the town of Siemensdorf in Germany. The unit was adopted as the SI standard for conductance in the 20th century.