Browse Definitions :
Definition

vacuum tube (VT, electron tube or valve)

Also see cathode ray tube ( CRT ), the specialized kind of vacuum tube that is in most desktop display monitors.

A vacuum tube (also called a VT,  electron tube or, in the UK, a valve ) is a device sometimes used to amplify electronic signals. In most applications, the vacuum tube is obsolete, having been replaced decades ago by the bipolar transistor and, more recently, by the field-effect transistor . However, tubes are still used in some high-power amplifiers, especially at microwave radio frequencies and in some hi-fi audio systems.

Tubes operate at higher voltages than transistors. A typical transistorized amplifier needs 6 to 12 volts to function; an equivalent tube type amplifier needs 200 to 400 volts. At the highest power levels, some tube circuits have power supplies delivering several kilovolts.

Vacuum tubes are making a comeback among audiophiles who insist that tubes deliver better audio quality than transistors. These old-fashioned components are more electrically rugged than their solid-state counterparts; a tube can often withstand temporary overload conditions and power-line transients that would instantly destroy a transistor.

The major disadvantages of tubes include the fact that they require bulky power supplies, and the high voltages can present an electric shock hazard.

This was last updated in March 2011
SearchCompliance
  • compliance risk

    Compliance risk is an organization's potential exposure to legal penalties, financial forfeiture and material loss, resulting ...

  • information governance

    Information governance is a holistic approach to managing corporate information by implementing processes, roles, controls and ...

  • enterprise document management (EDM)

    Enterprise document management (EDM) is a strategy for overseeing an organization's paper and electronic documents so they can be...

SearchSecurity
  • Extensible Authentication Protocol (EAP)

    The Extensible Authentication Protocol (EAP) is a protocol for wireless networks that expands the authentication methods used by ...

  • session key

    A session key is an encryption and decryption key that is randomly generated to ensure the security of a communications session ...

  • data breach

    A data breach is a cyber attack in which sensitive, confidential or otherwise protected data has been accessed and/or disclosed ...

SearchHealthIT
SearchDisasterRecovery
  • risk mitigation

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

  • call tree

    A call tree is a layered hierarchical communication model that is used to notify specific individuals of an event and coordinate ...

  • Disaster Recovery as a Service (DRaaS)

    Disaster recovery as a service (DRaaS) is the replication and hosting of physical or virtual servers by a third party to provide ...

SearchStorage
  • cloud storage

    Cloud storage is a service model in which data is transmitted and stored on remote storage systems, where it is maintained, ...

  • cloud testing

    Cloud testing is the process of using the cloud computing resources of a third-party service provider to test software ...

  • storage virtualization

    Storage virtualization is the pooling of physical storage from multiple storage devices into what appears to be a single storage ...

Close