3.5 Cooling/3.6 Power

How does airflow cool a computer?

• Fans pull cool air in, push hot air out

• Air flows over components → absorbs heat

• Good case layout improves airflow

Why is proper airflow important?

• Prevents overheating

• Improves performance & lifespan

• Poor airflow = trapped heat

What should you know about fan specifications?

• Standard sizes (80mm, 120mm, 200mm)

• Faster = more cooling but more noise

• Speed adjusts based on temperature

What is passive (fanless) cooling?

• No fans → silent operation

• Uses heat sinks only

• For low-power or quiet systems

What does a heat sink do?

• Dissipates heat via metal fins

• Increases surface area for cooling

• Made of aluminum or copper

What is thermal paste used for?

• Improves heat transfer between CPU & heat sink

• Fills air gaps

• Use small (pea-sized) amount

What is a thermal pad?

• Alternative to thermal paste

• Cleaner, easier to apply

• Less effective, not reusable

How does liquid cooling work?

• Coolant absorbs heat from CPU

• Moves to radiator → cooled by fans

• Used in high-performance systems (gaming, overclocking)

How are expansion cards cooled?

• High-end cards (GPUs) have built-in fans

• Direct airflow onto hot components

What does a computer power supply do?

• Converts AC → DC power

• Provides 3.3V, 5V, 12V to components

• Powers entire system

Why is the power supply important?

• Supplies power to all components

• Failure = system won’t run

• Critical for stability

What is the relationship between volts, amps, and watts?

• Watts = Volts × Amps

• Volts = electrical pressure

• Amps = flow of electricity

What is the difference between AC and DC?

• AC → alternating current (wall power)

• DC → direct current (used by computer)

• PSU converts AC → DC

What voltages are used by computer components?

• +12V → GPU, drives, fans

• +5V / +3.3V → motherboard, RAM

• +5VSB → standby power

What is the 24-pin motherboard connector?

• Main motherboard power

• Provides multiple voltages

• Replaced older 20-pin

What is a redundant power supply?

• Multiple PSUs in one system

• Each can handle full load

• Hot-swappable → no downtime

What is the difference between modular and fixed power supplies?

• Fixed → all cables attached

• Modular → removable cables

• Modular improves airflow & cable management

How do you choose the right power supply wattage?

• Add total system wattage

• GPUs use the most power

• Use ~50% capacity rule

Why is PSU efficiency important?

• Less energy wasted as heat

• More efficient (80–96%)

• Saves power and reduces cooling needs

What are basic electrical safety rules?

• Always disconnect power before working

• Never touch live electrical components