The following lines were added (+) and removed (-):
''As a general rule of thumb +/-5% is considered OK for voltage variation.'':'''A Closer Look at the Extra 4 Power Supply Pins'''The 4-pin +12V power connector is specified for all power supplies conforming to the ATX12V form factor, and consists of a Molex Mini-Fit, Jr. connector housing with female terminals. For reference, the connector is Molex part number 39-01-2040 and the terminals are part number 5556. This is the same style of connector as the ATX Main power connector, except with fewer pins.[[Image:PowerSupplyVoltageDataforPersonalComputers13.png]]You can use any of the black "ground" wires. There is a single green wire you must use for the jumper. While the jumper is connected the power supply should turn on and it will remain on as long as the jumper is connected. Once the jumper is removed then the power supply will turn off. === Legacy AT Motherboard Power Connector ===The original PC starting in 1981 used two cables (Molex 90331) to connect the power supply to the motherboard. They connected side by side into the motherboard, and they could easily be reversed accidentally, or inverted which will result in damage to the motherboard. When connecting them to the motherboard it was important to observe the "black to black" rule.{| cellpadding=0|- align="center"! colspan="3" bgcolor="#c0c0c0" | Pinout|- align="center"! bgcolor="#c0c0c0" | Pin number! bgcolor="#c0c0c0" | Wire color! bgcolor="#c0c0c0" | Description|-| align="center" | 1| align="center" | orange| align="center" | power good|-| align="center" | 2| align="center" | red| align="center" | +5 volts or connector key|-| align="center" | 3| align="center" | yellow| align="center" | +12 volts|-| align="center" | 4| align="center" | blue| align="center" | -12 volts|-| align="center" | 5| align="center" | black| align="center" | ground|-| align="center" | 6| align="center" | black| align="center" | ground|-| align="center" | 1| align="center" | black| align="center" | ground|-| align="center" | 2| align="center" | black| align="center" | ground|-| align="center" | 3| align="center" | white| align="center" | -5 volts|-| align="center" | 4| align="center" | red| align="center" | +5 volts|-| align="center" | 5| align="center" | red| align="center" | +5 volts|-| align="center" | 6| align="center" | red| align="center" | +5 volts|}On an AT system the power supply delivered a majority of power at 5 volts since most of the motherboard ran at that voltage. One rail was 5v and the other 12v. [[Image:PowerSupplyVoltageDataforPersonalComputers15.png]] == Additional Charts and Data ===== Power Connector List With Introduction Chronology ==={| border=1 cellpadding=0 cellspacing=0|- align="center"! bgcolor="#c0c0c0" | Version! bgcolor="#c0c0c0" | Introduction date! bgcolor="#c0c0c0" | Included connectors|-| align="center" | PC| align="center" | 1981|*original PC main power cables*4 pin peripheral cable|-| align="center" | ATX| align="center" | 1995|*20 pin main power cable*4 pin peripheral cable*floppy cable|-| align="center" | ATX12V 1.0| align="center" | 2000|*20 pin main power cable*4 pin 12 volt cable*6 pin auxiliary cable*4 pin peripheral cable*floppy cable|-| align="center" | ATX12V 1.3| align="center" | 2003|*20 pin main power cable*4 pin 12 volt cable*6 pin auxiliary cable*SATA cable*4 pin peripheral cable*floppy cable|-| align="center" | ATX12V 2.0| align="center" | 2003|*24 pin main power cable*4 pin 12 volt cable*6 Pin PCI Express power cable*SATA cable*4 pin peripheral cable*floppy cable|-| align="center" | EPS12V| align="center" | 2003|*24 pin main power cable*8 pin 12 volt cable*6 Pin PCI Express power cable*SATA cable*4 pin peripheral cable*floppy cable|-| align="center" | PCI Express 2.0| align="center" | 2007|*24 pin main power cable*4 pin 12 volt cable*8 pin 12 volt cable*6 Pin PCI Express power cable*8 Pin PCI Express power cable*SATA cable*4 pin peripheral cable*floppy cable|} === Connector Picture Chart ===[[Image:Connector-Picture-Chart.jpg]] === Inside the ATX Power Supply ===[[Image:PowerSupplyVoltageDataforPersonalComputers16.png]]The power supply can be fully discharged by connecting the black and red wires together. == Front Panel Header Connectors ==The most common question might be, which is positive, the white or the colored wire? For the LED connectors, the colored wire is usually indicative of a positive polarity. + colored wire - white[[Image:mobofrontpanelconnectors01.jpg]]For the power LED indicator, insert the connector with the colored wire into the header with the '+' mark. If you've connected it the other way around, you won't see the LED light up when the system is powered. Also observe the proper polarity when connecting the hard drive LED connector.[[Image:mobofrontpanelconnectors02.png]]For the power switch connector, polarity isn't really important. The same holds true for the reset connector. When you connect the speaker, you should observe proper polarity. Some motherboards have built-in buzzers and as such, the speaker connection is not needed. + red - black