Thats why all the connectors for which polarity matters (mainly the LEDs) are marked with a tiny sign or arrow to identify the positive wire.

A power cable from a 20-year-old computer will probably fit the one youre building today just fine.

Go to a computer shop and tell them you want to order a NEMA 5-15P to IEC-320-C13 cable.

That was kind of by design because older PATA drives were not supposed to be hot-swapped.

Because its become the new standard, practically all new power supplies come with a wealth of SATA connectors, but few or no Molex connectors.

Many have a 20-pin connector attached to a removable 4-pin connector.

If by sheer brawn you managed to make it fit backward, you would immediately fry every part of your computer the moment you turned it on.

Plugging an ATX power supply into AC power while the P1 connector is not connected to a load will destroy the power supply.

Some video cards can eat up 125 Watts of power or more just by themselves.

If the power cable wont attach to the input with just a little force, you probably have the plug reversed.

It was attached to a socket on the motherboard that usually was located very near the CPU.

As a general rule, if the motherboard has a socket for a P4 connection, it should be connected.

Newer devices tend to use either a SATA power connector (because power supplies tend to come with an abundance of them), or the 6- or 8-pin GPU connector described earlier in this page.

Its called a Molex or P5 connector (the P referring to power).

But this is an educational site, so consider this a history lesson.

If you manage to apply voltage to a component with the power connector reversed, you will immediately permanently destroy the device.

These provide both power and, in most cases, RPM monitoring and speed control based on temperature.

The header for the chassis fan may be labeled CHASSIS, SYS FAN, or CASE FAN Most modern motherboards also have a header for the chipset cooler.

Unless you like making noise, burning out fans, or wasting power, I dont think thats a good idea.

Fan speed regulation is one of those things that computers tend to do very well.

If you want to tweak your fan speeds, theres probably a setting in the CMOS setup for that.

The connectors usually include those for the power and reset switches, the power LED and hard drive activity LEDs, and on some cases, the system speaker.

That means it is possible to attach the leads in the wrong polarity.

Computer Front Panel Connector