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8/2/2019 What is Network Switch
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What is Network Switch - How
switches Works - Uses - Types of Switches
Network SwitchesIn the terminology of electronics, switch is an electronic device which breaks the circuit and thus
carries the current to different conducts. Whereas in networking, switches are referred as the
devices which are used to establish or connect a network.
Role of network switches
Large and small LAN networks require a bundle ofswitches for the network
connectivity. Various kinds of switches such as packet switches and network switches
are an integral part of the network. The purpose of switches is connect all kinds ofwhether traditional LAN s or SOHO networks. SOHO is a term given to a very small
enterprise comprising of more than or equal to ten people. The requirement of such
small networks is a single all purpose switch. This single switch serves the purpose of
connecting to DSL, WiFi and cable router. Typically switches operate at the data link
layer of the OSI model. Switches can operate at different OSI layers, and these multi
layered devices are called multi layer switches. Multi layer switches can operate at
data link layer, physical layer, transport and network layer. Switches are of many
types and they contain many ports. The presence of ports helps to connect or
maintain various networks as Fiber Channel, ATM and most commonly Ethernet. Layer
3 or the network layer of the OSI model is help switches to connect to the network
and process data. Network Switches are helpful in establishing all kinds of small
and large networks. For example in a large organization where there is a need to
connect various LANs to form one big WAN. The WAN router is often connected
through the switches.
Micro segmentation using network switches
Switches are dedicated, active and smart devices they work much more efficiently
than the other network devices. Switches are used to build micro segments in the
network. The purpose ofsegmentation is to abstain from the data and connections
to overlap each other. For example you establish a network connecting five or six
computers to each other as a, b, c, d, e. all these terminals are connected using five
switch port. Terminals such as a and b can transfer data to each other as well as
other 3 terminals without intermingling with each other. This efficiency and
unambiguous working of the network is due to the efficacy ofnetwork switches. If
we however connect our network with the hub alone, all terminals will share single
working unit hub. There would be chance of these devices to collide. Moreover the
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segmentation that the use of switches provides is helpful in attaining the full duplex
connection.
Types and uses of switches
The network switches serve innumerable purposes and uses. They are a reliable and
efficient way to establish connectivity. Switches are of many types depending on
the prototype in which they are used. The various categories of switches contained in
a network are unmanaged switches, managed switches. The least expansive
switches , that are used for single connection and small network operations is called
unmanaged switches. They are termed so because of their lack of configuration
crossing point. When the operation of the switches can be modified to perform
various operations, they are termed as managed switches. Managed switches are
preferred due to their adaptive configuration. Managed switches can create virtual
LANs and can also be used to alter the connection speed. Managed switches arefurther dived into two categories such as smart switches and enterprise managed
switches. The switches which have minimum management capability are called smart
switches. Whereas the switches, which can provide full line and web interface are
called enterprise switches. Enterprise switches are expense but they can be
customized for many uses.
What is a Switch?
A switch is used in a wired network to connect Ethernet cables from a number of
devices together. The switch allows each device to talk to the others. Switches aren't
used in networks with only wireless connections, since network devices such as
routers and adapters communicate directly with one another, with nothing in
between.
Although you can use the ports on the back of a router or modem to connect a few
Ethernet devices together, depending on the model, switches have a number of
advantages:
Switches allow dozens of devices to connect.
Switches keep traffic between two devices from getting in the way of yourother devices using the same network.
Switches allow control of who has access to various parts of the network. Switches allow you to monitor usage.
Switches allow communication (within your network) that's even faster thanthe Internet.
High-end switches have pluggable modules to tailor them to network needs.
Switches targeted for home uses, or for small businesses are described here.
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Switches targeted for larger networks, medium to large businesses are described
here. Due to their complexity, unlike with other NETGEAR products, Layer 3 Managed
Switches one of the available types of business switches do not have any free
support.
SwitchesSwitch Contacts - pole, throw etc.
Standard Switches- SPST, SPDT, DPST, DPDT.
Special Switches - multiway, key, tilt, reed etc.
Also see: Relays | Series and Parallel Connections - Switches
Circuit symbol for a
simple on-off switch
Selecting a Switch
There are three important features to consider when selecting a switch:
Contacts (e.g. single pole, double throw)
Ratings (maximum voltage and current)
Method of Operation (toggle, slide, key etc.)
Switch Contacts
Several terms are used to describe switch contacts:
Pole - number of switch contact sets.
Throw - number of conducting positions, single or double.
Way - number of conducting positions, three or more.
Momentary - switch returns to its normal position when released.
Open - off position, contacts not conducting. Closed - on position, contacts conducting, there may be several on positions.
For example: the simplest on-off switch has one set of contacts (single pole) and one
switching position which conducts (single throw). The switch mechanism has two
positions: open (off) and closed (on), but it is called 'single throw' because only one
position conducts.
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Switch Contact Ratings
Switch contacts are rated with a maximum voltage and current, and there may be
different ratings for AC and DC. The AC values are higher because the current falls to
zero many times each second and an arc is less likely to form across the switch
contacts.
For low voltage electronics projects the voltage rating will not matter, but you may
need to check the current rating. The maximum current is less for inductive loads
(coils and motors) because they cause more sparking at the contacts when switched
off.
Standard Switches
Type of Switch Circuit Symbol Example
ON-OFFSingle Pole, Single Throw = SPST
A simple on-off switch. This type can be
used to switch the power supply to a
circuit.
When used with mains electricity this
type of switch mustbe in the live wire,
but it is better to use a DPST switch to
isolate both live and neutral.
Photograph Rapid Electronics
SPST toggle switch
(ON)-OFFPush-to-make = SPST Momentary
A push-to-make switch returns to its
normally open (off) position when you
release the button, this is shown by the
brackets around ON. This is the standard
doorbell switch.
Photograph Rapid Electronics
Push-to-make switch
ON-(OFF)Push-to-break = SPST Momentary
A push-to-break switch returns to its
normally closed (on) position when you
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release the button.
Photograph Rapid ElectronicsPush-to-break switch
ON-ON
Single Pole, Double Throw = SPDT
This switch can be on in both positions,
switching on a separate device in each
case. It is often called a changeover
switch. For example, a SPDT switch can
be used to switch on a red lamp in one
position and a green lamp in the other
position.
A SPDT toggle switch may be used as a
simple on-off switch by connecting to COMand one of the A or B terminals shown in the
diagram. A and B are interchangeable so
switches are usually not labelled.
ON-OFF-ONSPDT Centre Off
A special version of the standard SPDT
switch. It has a third switching position
in the centre which is off. Momentary
(ON)-OFF-(ON) versions are also
available where the switch returns to thecentral off position when released.
Photographs Rapid Electronics
SPDT toggle switch
SPDT slide switch
(PCB mounting)
SPDT rocker switch
Dual ON-OFFDouble Pole, Single Throw = DPST
A pair of on-off switches which operate
together (shown by the dotted line in
the circuit symbol).
A DPST switch is often used to switch
mains electricity because it can isolate
both the live and neutral connections.
Photograph Rapid Electronics
DPST rocker switch
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Dual ON-ONDouble Pole, Double Throw = DPDT
A pair of on-on switches which operate
together (shown by the dotted line in
the circuit symbol).
A DPDT switch can be wired up as a
reversing switch for a motor as shown
in the diagram.
ON-OFF-ONDPDT Centre Off
A special version of the standard SPDT
switch. It has a third switching position
in the centre which is off. This can be
very useful for motor control becauseyou have forward, off and reverse
positions. Momentary (ON)-OFF-(ON)
versions are also available where the
switch returns to the central off position
when released.
Photograph Rapid Electronics
DPDT slide switch
Wiring for Reversing
Switch
Rapid Electronics stock a wide range of switches and
they have kindly allowed me to use their photographs on this page. The photographs
are from their Image Gallery CD-ROM.
Special Switches
Type of Switch Example
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Push-Push Switch (e.g. SPST = ON-OFF)
This looks like a momentary action push switch but it is a
standard on-off switch: push once to switch on, push
again to switch off. This is called a latching action.
Photograph Rapid Electronics
Microswitch (usually SPDT = ON-ON)
Microswitches are designed to switch fully open or closed
in response to small movements. They are available with
levers and rollers attached.
Photograph Rapid Electronics
Keyswitch
A key operated switch. The example shown is SPST.
Photograph Rapid Electronics
Tilt Switch (SPST)
Tilt switches contain a conductive liquid and when tiltedthis bridges the contacts inside, closing the switch. They
can be used as a sensor to detect the position of an
object. Some tilt switches contain mercury which is
poisonous.
Photograph Rapid Electronics
Reed Switch (usually SPST)
The contacts of a reed switch are closed by bringing a
small magnet near the switch. They are used in securitycircuits, for example to check that doors are closed.
Standard reed switches are SPST (simple on-off) but SPDT
(changeover) versions are also available.
Warning: reed switches have a glass body which is easily
broken! For advice on handling please see the
Electronics in Meccano website.
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Photograph Rapid Electronics
DIP Switch (DIP = Dual In-line Parallel)
This is a set of miniature SPST on-off switches, the
example shown has 8 switches. The package is the samesize as a standard DIL (Dual In-Line) integrated circuit.
This type of switch is used to set up circuits, e.g. setting
the code of a remote control.
Photograph Rapid Electronics
Multi-pole Switch
The picture shows a 6-pole double throw switch, also
known as a 6-pole changeover switch. It can be set tohave momentary or latching action. Latching action
means it behaves as a push-push switch, push once for
the first position, push again for the second position etc.
Photograph Rapid Electronics
Multi-way Switch
Multi-way switches have 3 or more conducting positions.
They may have several poles (contact sets). A popular
type has a rotary action and it is available with a range ofcontact arrangements from 1-pole 12-way to 4-pole 3 way.
The number of ways (switch positions) may be reduced by
adjusting a stop under the fixing nut. For example if you need a
2-pole 5-way switch you can buy the 2-pole 6-way version and
adjust the stop.
Contrast this multi-way switch (many switch positions) with the
multi-pole switch (many contact sets) described above.
Photograph Rapid Electronics
Multi-way rotary switch
1-pole 4-way switch symbol
Switches
Switches are electronic components which are used to break electrical circuits,
interrupting the current or diverting it from one conductor to another. They can
control the flow of power within a device, domestic circuit or appliance, and switches
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are found in all manually or automatically operated circuits. Rapid stocks a
comprehensive range of industrial switches, such as control unit switches, edge
switches, DIL switches, key and keyboard operated switches, latching PCB switches,
microswitches, push-button switches, rotary, toggle, slide and tactile switches.
Products from the industrys leading manufacturers, SCI, Bulgin and Camden Boss. If
you are looking for high quality switches for your application requirements and we donot have what you need today, we may be able to source these components for you.
Please contact us for details.
Switches
Control Unit Switches
(11)
DIL Switches
(41)
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Edge Switches
(7)
Key Operated Switches
(16)
Keyboard Switches
(13)
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Keypads
(43)
Latching PCB Switches
(28)
Microswitches
(57)
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Push-Button Switches
(125)
Rocker Switches
(37)
Rotary Switches
(17)
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Slide Switches
(16)
Tactile Switches
(111)
Toggle Switches
(64)
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