(1)keyboard connector
(2) mouse connector
(3) usb connector
(4)serial port connector
(5)power supply connector
(6)ATX connector
(7)AT and baby AT connector
(8)fan connector
(9)vcore connector
(10)cd audio jack connector
USB Connector
Universal serial bus is the latest craze in external device connector It is faster than Rs-232 serial Most importantly, all the USB devices attached to a computer(up to 127) consume a single interrupt(IRQ). If we have other USB devices such as a USB digital camera or modem we might able to save an interrupt by rutting mouse on the USB port as well When computer Boot up IRQ is reserved for all the peripherals connected to board but in case of the mouse or some other device is connected to the port than its driver will not be loaded and after starting operating system the connecting of mouse will not work but for the USB port whether the drive is connected or not the IRQ is reserved so that whenever we want to attach USB Camera it does not bother.Serial port connector
Conventionally serial ports more properly referred to as RS-232 These are mostly used to attach x86 computers modern computers use 9-pin serial port connectors generally that are used for mouse and connected at COM port m/b have 2 com ports COM 1 and COM 2 These days mouse port come separately and COM port are used for other devices to communicate.
power supply connector
Generally it has 4 wires for power conduction .these are plugged into the device in only one way .3.5 inch floppy use smaller connectors. Power splitter is used to split the power to connect more devices. One or two splitter probably does not constitute problem.
The connector has 4 wires.
(a)Red +5v DC
(b)Black GND
(c)Black GND
(d)Yellow +12v DC
ATX Connector
At is the newer version of AT/Baby AT. ATX motherboard use a single keyed power connector in contrast to the dual connectors of AT and Baby AT boards. The keyed ATX power connector makes it nearly impossible to destroy a motherboard by connecting power supply incorrectly. In addition ,ATX boards run on 3.3v eliminating the need of voltage regulator 
ATX boards also host a series of power related changes, allowing the computer to power itself off when the o.s. shuts down power itself on in response to specified events, go into low power mode and so on .
These are of 4 types-
(a)ATX
(b)Mini-ATX
(c)Micro-ATX
(d)Flex-ATX
AT and Baby AT connectors
This kind of connectors are used in small system like laptop and small cabinets this was used before ATX come for home uses.Generally they have 5-pin DIN connector.
AT and Baby AT motherboards used a pair of power connector, which had to be attached to the case’s power supply via cables permanently attached to the power supply in such case M/B voltage is 5v. But today’s motherboard required 3.3v.so such m/B required voltage regulators which converts 5v to 3.3v these voltage regulators produced heat and depending upon the amount of current drawn by the CPU could overheat and cause unreliable operation.
FAN Connector
CPU cooling FAN, system FAN has required power supply to move fan .these have 3 pin connector inserted at motherboard at particular place. 
V-core Connector
In some m/B there is no provision for internally give voltage to CPU like new boards. They have this connector which is key locked to m/B and give required voltage to CPU
CD audio jack Connector.
Different types of cards This connector has double ended. One inserted into CDROM drive and other end is connected to CD IN near the sound chip on motherboard. This is used in case of running audio CD without as interface.
There are of seven types of cards-
DISPLAY CARD
(a) CGA->
Ø color graphical adaptor
Ø This is of 9 pin card.
Ø 8088,80286,80386
Ø 8bit isa slot
(b) VGA->
Ø video graphical adaptor
Ø 15 pin cards.
Ø m/b 80486,PI
Ø 16bit/32bit/64bit.
(c) Dual CGA card->
Ø 9pin+25pin
Ø 9pin->monitor
Ø 25pin->printer
Ø 4 MB in size
IDE CARD [integrated device electronics]
Ø 16 bit cards.
Ø These cards are used for H.D.D and F.D.D control.
SIDE CARD [super integrated device electronics]
Ø F.D.C/H.D.C/MOUSE/PRINTER/GAME CONTROLLER
Ø 16bit/32bit
Ø Com1->mouse
Ø Com2->external modem[10 pin]
SOUND CARD
(a) non-pci->
Ø 16bit/32bit
(b) pci->
Ø 64bit
Ø in this card there is a 15 pin game controller and au out ,mic,Line in
Ø 4 MB in size
NETWORK CARD (LAN card)
(a) 32bit LAN card
Ø Speed is 10 MBits/s.
Ø There two types of connectors used.
· BNC->Broadcast network connector
· RJ->Register jack connector(RJ->45)
Boot rom->it is an IC used to boot all the other pc’s which has no hard disk but they can be boot with the help of network boot this process is done by the help of Boot rom.
b) 64 bit LAN card,
Ø Speed is 100Mb.
MODEM.
Ø Convert analog signal into digital signal and vice versa.
Ø There are two types of modem.
a) External Modem.
Ø Speed of the modem card 24/28/33/40/50/56.6Kbps
b) Internal Modem.
Ø Having same speed as external card .it is also PCI Card (64bit).its speed which is now a day used is 56.6Kbps.
TV-TUNNER CARD
Ø It is also a PCI card of 64 bit.
Ø it is two types
(a) Internal
(b)External
POWER SUPPLY
Most of the cases come with power supplies. Each variety of case -ATX, AT tower. It is possible to overload a power supply but power splitter. Since we know
WATTS=VOLTS*AMPS
Capacity of power supply measures in wattage. eg. if a 5v device draws 10 amps, it consumes 50 watts. As an example a computer with one 15a card, two PC cards, a 3.5 inch floppy disk ,two HDD, a cd-rom and two extra cooling fan.
Adding up these values, this computer requires 50.16w from 3.3v, 77.5w from 5v and 70.5w from 12v for a total of 198.16w. The motherboard consumes a few more watts, as well perhaps 25w or so depending on the board and cpu. Not all devices require their max. amounts of power at the same time. Typically for instance, harddisk require a great deal of power when they start up to over come the inertia inherent in stopped disk platters.
WIRES IN POWER SUPPLY
· The green wire, it present is a grounding wire. Attach it to any convenient metal part of the case.
· The black and white wires connect to the angled tabs on (toggle) the power switch.
· The brown and blue wires connect to the tabs that are parallel to one another on the switch. The brown and blue wires always carry current when the power supply is plugged in. Therefore, we should only try to connect or disconnect these wires ofter unplugging.
SWITCH MODE POWER SUPPLY(SMPS)
It is the power supply system used in the system box. The switch mode power supply(SMPS) is use 220v as the input and at the out it gives DC current with different values used by different component of the computer as +5v used by keyboard LED , +12v used by SMPS cooling fan and +12v for processor cooling fan. The out put power supply so we get form the SMPS while using the different type of color. They are basically of six color.
Different color wire from SMPS with the voltage they have-
yellow ----------->+12v
red ------------>+5v
black ------------>GND
blue ------------>-12v
white ------------>-5v
orange------------->power signal identify
We have two type of the SMPS cabinate-
ATX--->Advance Technology Exchange
AT ---->Advance Technology
· ATX cabinate has ATX SMPS have 20 pin with lock system.
It is an device which is used to store the elecric power when the main power supply is cut off by any reasion. Then we can use the power of the ups which is allready store in the UPS. It basically contain the storage battery which store the power supply. It take 220v as the input and gave 220v as the output. It also contain the transformer used to step up the electricity.
