Cooling and Power Lesson 005: Input and Output Voltages

Low Line Power

A 110-130 VAC US-based power supply.

High Line Power

A 220-240 VAC Europe and Asia-based power supply.

Why does the US have a different power standard?

Electricity was initially invented in multiple places using different types of systems.

Is it usually possible to use a laptop in countries with different power standards?

Yes, so long as you have the proper plug and power supply unit.

What voltages do most modern power supplies support?

Both low line and high line power.

Voltage Sensing/Dual Voltage Power Supplies

Automatically detects the outlet voltage and converts it into the proper DC voltage levels needed by the computer.

What will happen if a low voltage PSU is plugged into a high line power outlet?

It will break the PSU, possibly starting a fire.

What I'll happen if you plug a high voltage PSU into a low line power outlet?

It won't turn on and can lead to damage over time if left plugged in.

What are the four voltages that computers use?

+3.3 VDC, +5 VDC, +12 VDC, and -12 VDC.

Voltage Rail (Rail)

A wire that provides current at a particular voltage.

+3.3 VDC Rail

A cable or wire that provides +3.3 volts of usable current.

+5 VDC Rail

A cable or wire that provides 5 volts of usable current

+12 VDC Rail

A cable or wire that provides 12 volts of usable current.

-12 VDC Rail

A cable or wire that provides -12 volts of usable current.

What is the most common voltage rail used in modern PCs?

The 12 VDC rail.