Relays - Revision history

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	[[File:ElectroMechanicalRelay.jpg\|300px\|right]]		[[File:ElectroMechanicalRelay.jpg\|300px\|right]]
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			=====Description=====

	A [http://en.wikipedia.org/wiki/Relay '''relay'''] is a device which uses a small control current to '''[[Switches\|switch]]''' a much larger load current.They are used in switching circuits where the output of that circuit has insufficient power to drive the output device.		A [http://en.wikipedia.org/wiki/Relay '''relay'''] is a device which uses a small control current to '''[[Switches\|switch]]''' a much larger load current.They are used in switching circuits where the output of that circuit has insufficient power to drive the output device.

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	They have disadvantages in that they can only operate at low switching speeds and are relatively expensive.		They have disadvantages in that they can only operate at low switching speeds and are relatively expensive.


			=====Features and Applications=====

	The relay is energised by a control current passing through the magnet's coil attracting the armature and switching the load current. Types of relay coils can be driven by a.c. or d.c. and can vary between a few volts to several hundred.		The relay is energised by a control current passing through the magnet's coil attracting the armature and switching the load current. Types of relay coils can be driven by a.c. or d.c. and can vary between a few volts to several hundred.
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	For example, a DPDT (Double Pole, Double Throw) relay has two sets of contacts which switch at the same time.		For example, a DPDT (Double Pole, Double Throw) relay has two sets of contacts which switch at the same time.



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	The symbol for a double pole, single throw '''[[Switches\|(DPST)]]''' relay is shown together with a more simple representation of a relay for use in circuit diagrams.		The symbol for a double pole, single throw '''[[Switches\|(DPST)]]''' relay is shown together with a more simple representation of a relay for use in circuit diagrams.




	Relays, in common with many other electronic devices which include movement and an electro-magnetic coil, usually have a '''[[Diode\|diode]]''' connected in parallel to them to prevent damage caused by [http://en.wikipedia.org/wiki/Counter-electromotive_force '''Back-EMF''']		Relays, in common with many other electronic devices which include movement and an electro-magnetic coil, usually have a '''[[Diode\|diode]]''' connected in parallel to them to prevent damage caused by [http://en.wikipedia.org/wiki/Counter-electromotive_force '''Back-EMF''']




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			[[File:SolidStateRelay.jpg\|100px\|right]]

	~~[[File:SolidStateRelay.jpg\|100px\|right]]~~

			A [http://en.wikipedia.org/wiki/Solid-state_relay '''Solid State Relay ''(SSR)'''''] is a solid state electronic component that provides a similar function to an electromechanical relay but does not have any moving components, increasing long-term reliability.


	A [http://en.wikipedia.org/wiki/Solid-state_relay '''Solid State Relay ''(SSR)'''''] is a solid state electronic component that provides a similar function to an electromechanical relay but does not have any moving components, increasing long-term reliability.		{{Relays & Solenoids Buyers Guide}}


	[[Category:Secondary]]		[[Category:Secondary]]
	[[Category:Electronics Components]]		[[Category:Electronics Components]]

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	[[Category:Secondary]]		[[Category:Secondary]]
	[[Category:Electronics ~~and Control]]~~		[[Category:Electronics Components]]
	~~[[Category:Materials and~~ Components]]

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	A [http://en.wikipedia.org/wiki/Relay '''relay'''] is a device which uses a small control current to '''[[Switches\|switch]]''' a much larger load current.They are used in switching circuits where the output of that circuit has insufficient power to drive the output device.		A [http://en.wikipedia.org/wiki/Relay '''relay'''] is a device which uses a small control current to '''[[Switches\|switch]]''' a much larger load current.They are used in switching circuits where the output of that circuit has insufficient power to drive the output device.


			They have disadvantages in that they can only operate at low switching speeds and are relatively expensive.


			The relay is energised by a control current passing through the magnet's coil attracting the armature and switching the load current. Types of relay coils can be driven by a.c. or d.c. and can vary between a few volts to several hundred.


			The relay contacts are known as "normally open" (no),"normally closed" (nc) and "common" (c). They can be used to switch high voltages and currents depending upon the type. When the relay is "off" the common contact touches the normally closed contact. When the coil is energised the common contact switches to the normally open contact. In many relays the contacts are arranged in groups of three.

	~~They have disadvantages in that they can only operate~~ at ~~low switching speeds and are relatively expensive~~.
			For example, a DPDT (Double Pole, Double Throw) relay has two sets of contacts which switch at the same time.

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	[[Category:Secondary]]		[[Category:Secondary]]
	~~[[Category:Components]]~~
	[[Category:Electronics and Control]]		[[Category:Electronics and Control]]
			[[Category:Materials and Components]]

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	{{Secondary Electronics}}		[[Category:Secondary]]
			[[Category:Components]]
			[[Category:Electronics and Control]]

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	A [http://en.wikipedia.org/wiki/Solid-state_relay '''Solid State Relay ''(SSR)'''''] is a solid state electronic component that provides a similar function to an electromechanical relay but does not have any moving components, increasing long-term reliability.		A [http://en.wikipedia.org/wiki/Solid-state_relay '''Solid State Relay ''(SSR)'''''] is a solid state electronic component that provides a similar function to an electromechanical relay but does not have any moving components, increasing long-term reliability.
	~~[[Category:~~Electronics]]

			{{Secondary Electronics}}

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2014-11-13T16:31:10Z

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	A [http://en.wikipedia.org/wiki/Solid-state_relay '''Solid State Relay ''(SSR)'''''] is a solid state electronic component that provides a similar function to an electromechanical relay but does not have any moving components, increasing long-term reliability.		A [http://en.wikipedia.org/wiki/Solid-state_relay '''Solid State Relay ''(SSR)'''''] is a solid state electronic component that provides a similar function to an electromechanical relay but does not have any moving components, increasing long-term reliability.
			[[Category:Electronics]]

DT Online: Corrected link

2014-11-13T14:58:17Z

Corrected link

← Older revision		Revision as of 14:58, 13 November 2014
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	The symbol for a double pole, single throw '''[[(Switches\|(DPST)]]''' relay is shown together with a more simple representation of a relay for use in circuit diagrams.		The symbol for a double pole, single throw '''[[Switches\|(DPST)]]''' relay is shown together with a more simple representation of a relay for use in circuit diagrams.

DT Online: Relays

2014-11-12T21:05:14Z

Relays

New page

[[File:ElectroMechanicalRelay.jpg|300px|right]]
A [http://en.wikipedia.org/wiki/Relay '''relay'''] is a device which uses a small control current to '''[[Switches|switch]]''' a much larger load current.They are used in switching circuits where the output of that circuit has insufficient power to drive the output device.

They have disadvantages in that they can only operate at low switching speeds and are relatively expensive.

[[File:RelaySymbols.jpg|300px|right]]

The symbol for a double pole, single throw '''[[(Switches|(DPST)]]''' relay is shown together with a more simple representation of a relay for use in circuit diagrams.

Relays, in common with many other electronic devices which include movement and an electro-magnetic coil, usually have a '''[[Diode|diode]]''' connected in parallel to them to prevent damage caused by [http://en.wikipedia.org/wiki/Counter-electromotive_force '''Back-EMF''']

[[File:ReedRelay.jpg |100px|right]]

A [http://en.wikipedia.org/wiki/Reed_relay '''Reed Relay'''] is a '''[[Switches|reed switch]]''' enclosed in a '''[[Solenoid|solenoid]]'''.

[[File:SolidStateRelay.jpg|100px|right]]

A [http://en.wikipedia.org/wiki/Solid-state_relay '''Solid State Relay ''(SSR)'''''] is a solid state electronic component that provides a similar function to an electromechanical relay but does not have any moving components, increasing long-term reliability.