switch, electrical device having two states: on, or closed; and off, or open. Ideally a switch offers a zero impedance impedance, in electricity, measure in ohms of the degree to which an electric circuit resists the flow of electric current when a voltage is impressed across its terminals.
..... Click the link for more information. to a current when it is closed, and it offers infinite impedance when open. Mechanical switches, which operate by moving contacts together and apart, are often classified by the number of connections they can make or break at once and the number of closed positions in which they can be placed. A single-pole double-throw switch can be placed in either of two closed positions, making one connection in each position. A double-pole single-throw switch can open or close two connections at once. For many operations, as in computers and digital telecommunications, the operation of mechanical switches is too slow and transistors transistor, three-terminal, solid-state electronic device used for amplification and switching. It is the solid-state analog to the triode electron tube ; the transistor has replaced the electron tube for virtually all common applications.
..... Click the link for more information. are used instead. The PIN diode diode (dī`ōd), two-terminal electronic device that permits current flow predominantly in only one direction.
..... Click the link for more information. , which contains an intermediate intrinsic layer between the n-type and p-type layers, is also used as a simple switch. This device, which normally acts as a conductor, acts as a strong dielectric when the intrinsic layer is reverse biased. See relay relay, electromechanical switch operated by a flow of electricity in one circuit and controlling the flow of electricity in another circuit. A relay consists basically of an electromagnet with a soft iron bar, called an armature, held close to it.
..... Click the link for more information. .
switch
switch [swich]
..... Click the link for more information. to a current when it is closed, and it offers infinite impedance when open. Mechanical switches, which operate by moving contacts together and apart, are often classified by the number of connections they can make or break at once and the number of closed positions in which they can be placed. A single-pole double-throw switch can be placed in either of two closed positions, making one connection in each position. A double-pole single-throw switch can open or close two connections at once. For many operations, as in computers and digital telecommunications, the operation of mechanical switches is too slow and transistors transistor, three-terminal, solid-state electronic device used for amplification and switching. It is the solid-state analog to the triode electron tube ; the transistor has replaced the electron tube for virtually all common applications.
..... Click the link for more information. are used instead. The PIN diode diode (dī`ōd), two-terminal electronic device that permits current flow predominantly in only one direction.
..... Click the link for more information. , which contains an intermediate intrinsic layer between the n-type and p-type layers, is also used as a simple switch. This device, which normally acts as a conductor, acts as a strong dielectric when the intrinsic layer is reverse biased. See relay relay, electromechanical switch operated by a flow of electricity in one circuit and controlling the flow of electricity in another circuit. A relay consists basically of an electromagnet with a soft iron bar, called an armature, held close to it.
..... Click the link for more information. .
Bibliography
See J. C. McDonald, Fundamentals of Digital Switching (1990).
switch
(1) A mechanical or electronic device that directs the flow of electrical or optical signals from one side to the other. Switches with more than two ports, such as a LAN switch or PBX, are able to route traffic. See LAN switch, softswitch, PBX, data switch and transistor.
With regard to a simple on/off switch, remember... Open is "off." Closed is "on."
(2) In programming, a bit or byte used to keep track of something. Sometimes refers to a branch in a program.
(3) A modifier of a command. See DOS switch.
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| Mechanical and Semiconductor Switches |
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| The semiconductor switch (transistor) performs the same function as an on/off light switch on the wall. Instead of being manually closed, the switch is electronically closed by pulsing the semiconductor material, which makes it conduct. |
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| A Manual Switch |
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| This early switch panel from New York Electric Switchboard Company was used to manually open and close electric lines. |
switch
1. a mechanical, electrical, electronic, or optical device for opening or closing a circuit or for diverting energy from one part of a circuit to another
2. the tassel-like tip of the tail of cattle and certain other animals
3. any of various card games in which the suit is changed during play
4. US and Canadian a railway siding
5. US and Canadian a railway point
switch [swich]
(computer science)
A hardware or programmed device for indicating that one of several alternative states or conditions have been chosen, or to interchange or exchange two data items.
A symbol used to indicate a branch point, or a set of instructions to condition a branch.
(civil engineering)
A device for enabling a railway car to pass from one track to another.
The junction of two tracks.
(electricity)
A manual or mechanically actuated device for making, breaking, or changing the connections in an electric circuit. Also known as electric switch. Symbolized SW.
| 1. | (programming) | switch - switch statement. | |
| 2. | (software) | switch - command line option. | |
| 3. | (networking) | switch - packet switch, circuit switch. |
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