Computer Power Specifications - CompTIA A+ 220-801: 1.8

Amp and volt

• Ampere (amp, A)- The rate of electron flow past a point in one second
• 1 Amp = 6.242 x 10 18 electrons per second
• Voltage (volt, V) - Electrical "pressure" pushing the electrons

Power

• Watt (W) - Measurement of real power use
• volts * amps = watts
• 120V * 0.5A = 60W

Current

• Alternating current (AC) 

•  Direction of current constantly reverses
• Distributes electricity efficiently over long distances
• Frequency of this is cycle is important
• US/Canada - 110 to 120 volts of AC (VAC), 60 hertz (Hz)
• Europe - 220-240VAC, 50Hz

• Direct Current (DC)

• Current moves in one direction with a constant voltage

ATX Power supply

ATX Modular Power supply

 Micro ATX Power Supply

 Set your voltage before plugging it in!

• Manually switch between 115V and 230V
• Get your meter
• Don't plug a 115V power supply into a 230V power source!