The power supply converts the alternating current (AC) line from your home to the direct current (DC) needed by the personal computer. The power supply is the most important component in a computer. It supplies power to all of the devices in your computer from the motherboard to your storage devices. A power supply has multiple colored wires and connectors that extend from it to hook to your devices. The largest connector hooks to the motherboard. It is not necessary to hook up every connector on the power supply. A power supply contains a large coil that stores power for long periods of time. NEVER open a power supply. There is enough power stored in one that it could seriously hurt someone.

Power Supply Specifications

Power supplies are rated in Watts (W). They range from 250W and upwards. Depending on the amount of devices you have in your computer you may need a larger power supply. You never want the power consumption of the computer to equal the output of the power supply. Power supplies should never be run at 100% of their capacity. According to PC Power & Cooling, Inc., some power consumption values (in watts) for common items in a personal computer are:

Common Power Consumption in Watts

Power Supply Problems  

• Computer will not power on

• The computer shuts itself off at odd intervals

• The fan in the power supply is making a lot of noise or not working

Power Supply Troubleshooting

 If your computer will not power on;

• Check that all cables are plugged in correctly outside the computer

• Swap the monitor power cord with the one on the tower

• Check that the power cables are hooked up inside the computer

• Listen for any sign of noise from the system or any lights indicating that it is receiving power

• Check the voltage switch on the back of the computer for correct settings

 If your computer is turning itself off at odd intervals it could be a sign that your computer is overheating.

• Check to make sure that your computer has adequate ventilation and that the fans are spinning

• Clean the fans with a cotton swab and alcohol if it is dirty

 If your power supply is making noise or the fan is not working, check to make sure that the fan is clean.

Knowledge Check #3

How much power does a Network Interface card consume in Watts?

a. 5W

b. 4W

c. 10W

d. Don't know the answer

Please include your answer to this question in the email that you started previously.

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