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 In most applications, the vacuum tube is obsolete, having been replaced decades ago by the bipolar transistor and, more recently, by the field-effect transistor .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

  • 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...

  • risk assessment

    Risk assessment is the identification of hazards that could negatively impact an organization's ability to conduct business.

SearchSecurity

  • honeypot (computing)

    A honeypot is a network-attached system set up as a decoy to lure cyber attackers and detect, deflect and study hacking attempts ...

  • spam trap

    A spam trap is an email address that is used to identify and monitor spam email.

  • cracker

    A cracker is someone who breaks into someone else's computer system, often on a network; bypasses passwords or licenses in ...

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

  • storage virtualization

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

  • erasure coding

    Erasure coding (EC) is a method of data protection in which data is broken into fragments, expanded and encoded with redundant ...

  • continuous data protection

    Continuous data protection (CDP), also known as continuous backup, is a backup and recovery storage system in which all the data ...

Close