| A | B |
|---|
| Active power factor correction (active PFC) | Circuitry built into PC power supplies to reduce harmonics |
| Alternating current (AC) | Type of electricity in which the flow of electrons alternates direction, back and forth, in a circuit |
| Amperes (amps or A) | Unit of measure for amperage, or electrical current |
| Direct current (DC) | Type of electricity in which the flow of electrons is in a complete circle in one direction |
| Field replaceable unit (FRU) | Formal term for math coprocessor (also called a numeric processor) circuitry inside a CPU. A math coprocessor calculates by using a floating point math (which allows for decimals). Before the Intel 80486, FPUs were separate chips from the CPU. |
| IEC-320 | Connects the cable supplying AC power from a wall outlet into the power supply |
| Joule | Unit of energy describing (in this book) how much energy a surge suppressor can handle before it fails |
| Mini connector | One type of power connector from a PC power supply unit. Supplies 5 to 12 volts to peripherals. Also known as a floppy connector |
| Molex connector | Computer power connector used by CD-ROM drives, hard drives, and case fans. Keyed to prevent it from being inserted into a power port improperly |
| Multimeter | Device used to measure voltage, amperage, and resistance |
| Ohms | Electronic measurement of a cable’s impedance |
| PI power connector | Provides power to ATX motherboards |
| Power conditioning | Ensuring and adjusting incoming AC wall power to as close to standard as possible. Most UPS devices provide power conditioning |
| Power supply fan | Small fan located in a system power supply that draws warm air from inside the power supply and exhausts it to the outside |
| Power supply unit (PSU) | Provides the electrical power for a PC. Converts standard AC power into various voltages of DC electricity in a PC |
| Rails | Separate DC paths within an ATX power supply |
| Resistance | Difficulty in making electricity flow through a material, measured in ohms |
| SATA power connector | Serialized version of the ATA standard that offers many advantages over PATA (parallel ATA) technology, including thinner cabling, keyed connectors, and lower power requirements |
| Slot covers | Metal plates that cover up unused expansion slots on the back of a PC. Useful in maintaining proper airflow through a computer case |
| Soft power | Characteristic of ATX motherboards, which can use software to turn the PC on and off. The physical manifestation of soft power is the power switch. Instead of the thick power cord used in AT systems, an ATX power switch is little more than a pair of small wires leading to the motherboard. |
| Surge suppressor | Inexpensive device that protects your computer from voltage spikes |
| Uninterruptible power supply (UPS) | Device that supplies continuous clean power to a computer system the whole time the computer is on. Protects against power outages and sags |
| Volts (V) | Measurement of the pressure of the electrons passing through a wire, or voltage |
| Wattage (watts or W) | Measurement of the amps and volts needed for a particular device to function |
