Chapter 5: Power Flashcards
Voltage
A representation of potential energy, measured in volts (V)
Wattage (Electric power)
The rate of electric energy in a circuit measured in watts (W)
Amperage or electric current
The movement of electric charge measured in amperes or amps (A)
Impedance
The amount of resistance to electricity, measured in ohms (Ω)
Multimeter
A handheld device that can be used to measure amps and impedance and to test voltage inside a computer and from AC outlets
Clean power
When voltage is steady
Dirty power
When voltage fluctuates
Surge
An unexpected increase in the amount of voltage provided
Spike
A short transient in voltage that can be due to a short circuit, tripped circuit breaker, power outage, or lightning strike
Sag
An unexpected decrease in the amount of voltage provided
Brownout
When voltage drops to such an extent that it causes the lights to dim and causes computers to shut off
Blackout
When a total loss of power for a prolonged period occurs
Power Strip
Group of sockets usually in-line that includes a flexible cable that plugs into an AC outlet; Allows multiple devices to share a single receptacle in that outlet
Surge Protector
A power strip that also incorporates a metal-oxide varistor (MOV) to protect against surges and spikes; Usually rated in joules (more the better)
Uninterruptible power supply (UPS)
Takes the functionality of a surge protector and combines it with a battery backup to protect from sags, brownouts, and blackouts; Output power capacity rated in volt-amps (VA) and watts
Power Supply Unit (PSU)
Converts AC drawn from the wall outlet into DC using a transformer and rectifier to be used internally by the computer
Dual-Rail PSU
Separates and limits the current through each wire to avoid overheating
Desktop
Lies horizontally; Usually has one or two 5 1/4 inch drive bays
Mini-Tower
Stands vertically; Usually has two or three drive bays
Mid-Tower
Usually has three or four bays
Full-Tower
Usually has six bays
Slim line
Usually stands vertically; small form factor (SFF); e.g. mini-ITX systems and microATX
All-in-One (AOC)
The computer case and components are integrated into the monitor. This could be a monitor that is meant to sit on a desktop or a handheld device with touchscreen
