Power Supplies and cooling

Power Supply Unit (PSU)

Delivers low-voltage direct current (DC) power to PC components. Contains a rectifier, transformers, regulators, filters, and a fan.

Rectifier

Converts alternating current (AC) from the building outlet into direct current (DC) for internal hardware.

Transformer

Steps down high incoming AC voltage to lower, safe operating DC voltages.

Regulators & Filters

Ensures consistent voltage output and smooths out power delivery to protect components from fluctuations.

ATX Form Factor (PSU)

Standard physical shape, mounting screw positions, and connector layout for desktop power supplies to fit cases and motherboards.

Low-Line Voltage

Standard AC power in North America, delivering 120 VAC (100–127 VAC tolerance range).

High-Line Voltage

Standard AC power in the UK, Europe, and data centers, delivering 230 VAC (220–240 VAC tolerance range) for higher efficiency.

Auto-Switching PSU

Automatically detects incoming AC voltage (low-line vs. high-line) and adjusts internally without needing a manual switch.

Wattage Rating

The maximum output capability of a PSU measured in watts, calculated as Voltage multiplied by Current (V * I).

Underpowered PSU Risks

Causes system instability (random reboots, crashes, shutdowns) and potential hardware damage due to overheating.

+12 VDC Rail

The most critical power rail in modern PCs; feeds high-wattage demand to the CPU and dedicated graphics cards.

PSU Rail

An internal wire distribution path supplying current at a specific output voltage (+3.3V, +5V, +12V, -12V).

80 PLUS Certification

Energy efficiency rating program certifying that a PSU operates at a minimum of 80% efficiency at specified load levels.

PSU Energy Inefficiency

Excess power drawn from the wall that gets lost as heat, increasing electrical costs and thermal stress on the system.

80 PLUS Bronze

Efficiency rating of at least 82% at 20% load, 85% at 50% load, and 82% at 100% load.

80 PLUS Silver

Efficiency rating of at least 85% at 20% load, 88% at 50% load, and 85% at 100% load.

80 PLUS Gold

Efficiency rating of at least 87% at 20% load, 90% at 50% load, and 87% at 100% load.

80 PLUS Platinum

Efficiency rating of at least 90% at 20% load, 92% at 50% load, and 89% at 100% load.

80 PLUS Titanium

Efficiency rating requiring 90% at 10% load, 92% at 20% load, 94% at 50% load, and 90% at 100% load.

P1 Power Connector

Primary motherboard power connection (24-pin or 20+4-pin breakout) supplying 3.3V, 5V, and 12V DC power.

P1 Wire Colors

Black = Ground, Yellow = +12V, Red = +5V, Orange = +3.3V.

Modular Power Supply

Features detachable power cables, allowing you to plug in only needed wires to reduce internal clutter and improve airflow.

Non-Modular Power Supply

All power cables are permanently attached; extra unused cables must be stowed inside the case where they block airflow.

Redundant Power Supply

Dual PSUs in enterprise servers configured in failover mode so if one fails, the other immediately takes over to prevent downtime.

Backplane

Server circuit board connecting redundant power supply modules to allow hot-swappable replacements.

Hot-Swappable Component

A hardware part (like a server PSU) that can be removed and replaced while the main system stays running continuously.

Passive Heat Sink

Metal block with fins (e.g., RAM heat spreader) relying solely on expanded surface area and ambient air movement without a fan.

Active Heat Sink

Finned copper or aluminum block paired directly with an electric fan to create forced air convection for high-heat chips.

Thermal Paste / Pad

Applied between the CPU lid and heat sink block to eliminate microscopic air gaps and ensure maximum conductive heat transfer.

Thermal Pads

Solid pre-cut interface blocks that soften when heated; easier to apply than paste but generally less efficient at heat transfer.

Heat Sink Push Pins

Mounting clips used to secure CPU heat sinks to motherboards; released and reset with a half-turn of a screwdriver.

Chassis Fans

Direct intake and exhaust airflow through case vents—drawing cool air in through front vents and expelling hot air out the rear.

Plastic Shrouds / Baffles

Internal plastic channels attached with clips to direct fan airflow explicitly across the CPU.

Open-Loop Liquid Cooling

Custom cooling system pumping liquid coolant through a reservoir, pump, water blocks, tubing, and radiators.

Water Block

Copper or aluminum fluid chamber attached to a CPU or GPU that transfers component heat into circulating liquid coolant.

Radiator & Fans

Cooling assembly positioned at chassis vents that dispels heat from circulating liquid coolant into the outside air.

Closed-Loop (AIO) Cooler

Pre-filled, sealed liquid cooling unit designed for a single component (CPU/GPU) requiring zero fluid maintenance.

Open-Loop Maintenance

Requires periodic draining, cleaning, and refilling of coolant, keeping radiator fins dust-free, and draining liquid before moving the PC.