Computer fan in the context of Fan (machine)

All electronic devices and circuitry generate excess heat and thus require thermal management to improve reliability and prevent premature failure. The amount of heat output is equal to the power input, if there are no other energy interactions. There are several techniques for cooling including various styles of heat sinks, thermoelectric coolers, forced air systems and fans, heat pipes, and others. In cases of extreme low environmental temperatures, it may actually be necessary to heat the electronic components to achieve satisfactory operation.

Computer cooling is required to remove the waste heat produced by computer hardware, to keep components within permissible operating temperature limits. Components that are susceptible to temporary malfunction or permanent failure if overheated include integrated circuits such as central processing units (CPUs), chipsets, graphics cards, hard disk drives, and solid state drives (SSDs).

Components are often designed to generate as little heat as possible, and computers and operating systems may be designed to reduce power consumption and consequent heating according to workload, but more heat may still be produced than can be removed without attention to cooling. Use of heatsinks cooled by airflow reduces the temperature rise produced by a given amount of heat. Attention to patterns of airflow can prevent the development of hotspots. Computer fans are widely used along with heatsink fans to reduce temperature by actively exhausting hot air. There are also other cooling techniques, such as liquid cooling. All modern day processors are designed to cut out or reduce their voltage or clock speed if the internal temperature of the processor exceeds a specified limit. This is generally known as Thermal Throttling in the case of reduction of clock speeds, or Thermal Shutdown in the case of a complete shutdown of the device or system.

A computer case, also known as a computer chassis, is the enclosure that contains most of the hardware of a personal computer. The components housed inside the case (such as the CPU, motherboard, memory, mass storage devices, power supply unit and various expansion cards) are referred as the internal hardware, while hardware outside the case (typically cable-linked or plug-and-play devices such as the display, speakers, keyboard, mouse and USB flash drives) are known as peripherals.

Conventional computer cases are fully enclosed, with small holes (mostly in the back panel) that allow ventilation and cutout openings that provide access to plugs/sockets (back) and removable media drive bays (front). The structural frame (chassis) of a case is usually constructed from rigid metals such as steel (often SECC — steel, electrogalvanized, cold-rolled, coil) and aluminium alloy, with hardpoints and through holes for mounting internal hardware, case fans/coolers and for organizing cable management. The external case panels, at least one of which are removable, cover the chassis from the front, sides and top to shield the internal components from physical intrusion and dust collection, and are typically made from painted metallic and/or plastic material, while other materials such as mesh, tempered glass, acrylic, wood and even Lego bricks have appeared in many modern commercial or home-built cases. In recent years, open frame or open air cases that are only partly enclosed (with freer ventilation and thus theoretically better cooling) have become available in the premium gaming PC market.