Chapter Overview • Power Supplies • Power Supply Problems
Overview of Power Supplies • The standard power supply • Converts AC to DC • “Conditions” power by evening out fluctuations • Requires a fan • Standard power in U.S. is 110 volts alternating current (VAC) oscillating at 60 hertz (Hz). • You must consider physical size, wattage, and connector types when replacing a power supply.
Power Supply Sizes • Power supply sizes are based on the type of case and motherboard connections. • The AT-style is found on older computers and earlier Pentium systems. • The ATX-style (current technology) is found on Pentium II and later systems. • You should compare the existing power supply with the new one before replacing it.
Power Supply Wattage • A watt is a unit of electrical power equivalent to one volt-ampere. • Total wattage needs are determined by adding the power required for each device, plus more power for startup. • General-use computers require 130–205 watts. • Servers and high-performance workstations require 350–500 watts.
Extenders and Splitters • An extender lengthens the reach of a power connector. • A splitter increases the number of connections.
Power Failures • Power failures can have internal or external causes. • External failures, which are more common, include • Surges • Spikes • Sags • Brownouts • Blackouts
Power Protection Devices • A surge suppressor • Filters the effects of voltage spikes and surges • Smoothes out power variations • An uninterruptible power supply (UPS) is an inline battery backup.
Chapter Summary • The AT-style power supply is used for older motherboards and the ATX-style power supply is used for newer motherboards. • Peripheral devices use Molex connectors and mini connectors. • Different types of power failures can cause computer problems and can damage computer equipment. • Surge suppressors and UPS devices can protect computer equipment.