Lecture Notes: Understanding Computer Power Supplies and Electricity

Power Supply Basics

• Purpose: Converts AC (alternating current) from the wall to DC (direct current) usable by computers.
• Components:
  • Fan for cooling.
  • Voltage information printed on the unit.
  • Cables to connect to the motherboard and wall outlet.

Electricity Types

• AC (Alternating Current): Changes direction periodically.
• DC (Direct Current): Flows in a single direction.
• Computers Use DC: Power supplies convert AC to DC.

Understanding Electricity via Water Pipe Analogy

• Voltage: Comparable to water pressure.
  • Higher voltage = more electricity flow.
• Current (Amperage): Comparable to water flow rate.
  • Measured in amps; pulls electricity needed.
• Wattage: Combination of volts and amps required by a device.

Voltage and Appliances

• Correct Voltage: Vital for proper device functioning.
  • Using incorrect voltage can damage devices.
• Example: Plugging 120V appliance into 220V outlet can fry the appliance.
  • Opposite scenario: appliance may work slowly, possibly damaging it over time.

Current and Charging

• Amps: Measure the rate of electrical flow.
  • Higher amps can charge devices faster.
• Example: 2.1 amps charger charges faster than a 1 amp charger.

Wattage Considerations

• Power Supply Sizing:
  • Too low wattage: insufficient power for the computer.
  • Larger power supply: provides only needed power, doesn't harm the computer.
• Typical Sizes:
  • Basic desktops: ~500 watt sufficient.
  • High-demand activities (gaming, video editing): require more powerful supplies.

Diagnosing Power Issues

• Symptoms of a Bad Power Supply:
  • Computer fails to turn on.
  • Possible issues: burnouts, power surges, lightning strikes.
• IT Support Skill: Essential to diagnose and replace failed power supplies.