what is a relay?

what are the functions of a relay and is made up of a relay?

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  • bob
    Lv 6
    1 decade ago
    Best Answer

    relay is an electrical switch that opens and closes under the control of another electrical circuit. In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts. It was invented by Joseph Henry in 1835. Because a relay is able to control an output circuit of higher power than the input circuit, it can be considered to be, in a broad sense, a form of an electrical amplifier.

    When a current flows through the coil, the resulting magnetic field attracts an armature that is mechanically linked to a moving contact. The movement either makes or breaks a connection with a fixed contact. When the current to the coil is switched off, the armature is returned by a force approximately half as strong as the magnetic force to its relaxed position. Usually this is a spring, but gravity is also used commonly in industrial motor starters. Most relays are manufactured to operate quickly. In a low voltage application, this is to reduce noise. In a high voltage or high current application, this is to reduce arcing.

  • Robert
    Lv 4
    4 years ago

    A relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays. Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuits), or where several circuits must be controlled by one signal. The first relays were used in long distance telegraph circuits as amplifiers: they repeated the signal coming in from one circuit and re-transmitted it on another circuit. Relays were used extensively in telephone exchanges and early computers to perform logical operations.

    https://www.electrikals.com/products/r/relays?cid=...

  • shaun
    Lv 4
    4 years ago

    A relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays.

  • A.V.R.
    Lv 7
    1 decade ago

    A relay (electrical) comes 'on' when its input comes'on'. In this sense it relays the incoming information ahead.

    It can be electromechanical, solid state, or IC.

    A relay can operate with a small signal and control high power. It can provide electrical isolation between the input and the output.

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  • 1 decade ago

    1 a: a supply (as of horses) arranged beforehand for successive relief b: a number of persons who relieve others in some work <worked in relays around the clock>2 a: a race between teams in which each team member successively covers a specified portion of the course b: one of the divisions of a relay3: an electromagnetic device for remote or automatic control that is actuated by variation in conditions of an electric circuit and that operates in turn other devices (as switches) in the same or a different circuit4: servomotor5: the act of passing along (as a message or ball) by stages; also : one of such stages

  • Anonymous
    1 decade ago

    Check out this:)

    -An act of passing something along from one person, group, or station to another.

    -Sports.

    -A relay race.

    -A division of a relay race.

    -Electronics. A device that responds to a small current or voltage change by activating switches or other devices in an electric circuit.

    -A crew of workers who relieve another crew; a shift.

    -A fresh team, as of horses or dogs, to relieve weary animals in a hunt, task, or journey.

    -tr.v., -layed, -lay·ing, -lays. (rē'lā, rĭ-lā')

    -To pass along by or as if by relay: relayed the message to his boss.

    -To supply with fresh relays.

    -Electronics. To control or retransmit by means of a relay.

  • Anonymous
    4 years ago

    Ditto here (yahoo.ie address). Problem for about 8-10 days now, contacted support about a week ago, no response. You'd think they'd post something, somewhere acknowledging the issue. I've lost shopping order e-mails, ebay mails, mails from work, mails from friends. People should jump ship to Gmail if this goes on any longer. Poor show by Yahoo.

  • john
    Lv 4
    4 years ago

    A device that responds to a small current or voltage change by activating switches or other devices in an electric circuit.

  • 1 decade ago

    a relay is a solinoid switch sort of . it delays current through the solinoid in it before the switch cloese. it is like a build up system to start up a unit eg compressor etc

  • 1 decade ago

    a curcit made of four things in aloop

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