Browse Definitions :
Definition

siemens (mho)

Contributor(s): Gary Marcantoni

(Siemens AG is a German company engaged in electrical engineering and electronics.)

The siemens (symbolized S) is the Standard International (SI) unit of electrical conductance. The archaic term for this unit is the mho (ohm spelled backwards). Siemens are also used, when multiplied by imaginary numbers, to denote susceptance in alternating current (AC) and radio frequency (RF) applications. Reduced to base SI units, 1 S is the equivalent of one second cubed ampere squared per kilogram per meter squared (1 s3 · A2 · kg-1 · m-2). The siemens is also the equivalent of an ampere per volt (A/V).

In a direct current (DC) circuit, a component has a conductance of 1 S when a potential difference of one volt (1 V) produces a current of one ampere (1 A) through the component. Thus, one siemens is the equivalent of one ohm. But mathematically, resistance and conductance are reciprocals of each other. If R is the resistance of a component in ohms and G is the conductance in siemens,

R = 1 / G

and

G = 1 / R

In AC and RF circuits, conductive siemens behave the same as they do in DC circuits, provided the root-mean-square (rms) AC voltage is specified. In AC and RF circuits, susceptance exists only when there is a net capacitance or inductance. Capacitive susceptances have positive imaginary number values; inductive susceptances have negative imaginary-number values. The susceptance of a particular capacitor or inductor depends on the frequency.

Conductances and susceptances are sometimes expressed in units representing power-of-10 multiples or fractions of 1 S. A kilosiemens (1 kS) is equal to one thousand (103) siemens. A megasiemens (1 MS) is equal to one million (106) siemens. A millisiemens (1 mS) is equal to one-thousandth (10-3) of a siemens. A microsiemens (1 uS) is equal to one-millionth (10-6) of a siemens.

Also see conductance, Ohm's Law, prefix multipliers, resistance, reactance, ohm, and Standard International (SI) system of units.

This was last updated in February 2008

Continue Reading About siemens (mho)

Start the conversation

Send me notifications when other members comment.

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

Powered by:

SearchCompliance

  • regulatory compliance

    Regulatory compliance is an organization's adherence to laws, regulations, guidelines and specifications relevant to its business...

  • Whistleblower Protection Act

    The Whistleblower Protection Act of 1989 is a law that protects federal government employees in the United States from ...

  • smart contract

    A smart contract, also known as a cryptocontract, is a computer program that directly controls the transfer of digital currencies...

SearchSecurity

  • RSA algorithm (Rivest-Shamir-Adleman)

    The RSA algorithm is the basis of a cryptosystem -- a suite of cryptographic algorithms that are used for specific security ...

  • remote access

    Remote access is the ability to access a computer or a network remotely through a network connection.

  • IP Spoofing

    IP spoofing is the crafting of Internet Protocol (IP) packets with a source IP address that has been modified to impersonate ...

SearchHealthIT

SearchDisasterRecovery

  • virtual disaster recovery

    Virtual disaster recovery is a type of DR that typically involves replication and allows a user to fail over to virtualized ...

  • tabletop exercise (TTX)

    A tabletop exercise (TTX) is a disaster preparedness activity that takes participants through the process of dealing with a ...

  • risk mitigation

    Risk mitigation is a strategy to prepare for and lessen the effects of threats faced by a data center.

SearchStorage

  • disk array

    A disk array, also called a storage array, is a data storage system used for block-based storage, file-based storage or object ...

  • enterprise storage

    Enterprise storage is a centralized repository for business information that provides common data management, protection and data...

  • optical storage

    Optical storage is any storage type in which data is written and read with a laser. Typically, data is written to optical media, ...

Close