page_title: Computer fan
section_title: Case fan
hierarchical_section_title: Computer fan / Applications / Case fan
caption_attribution_description: English: Two fans installed by default on the computer case be quiet BG021. The smallest 12cm fan running at 1200 rpm is located at the back of the case to extract the air from the processor whose the air cooling is close. It can not be bigger because it has to share the backspace with the outputs of the motherboard. The largest 14cm fan rotating at 900 rpm is located on the front panel and will suck outside air to inject it into the case. By rotating faster the smaller fan will allow a flow comparable to the largest, it allows to have a balance between the air drawn and extracted from the case for optimal ventilation. Français&#160;: Deux ventilateurs installés par défaut sur le boitier d'ordinateur be quiet BG021. Le plus petit ventilateur de 12cm tournant à 1200 tr/min est situé à l'arrière du boitier pour extraire l'air du processeur donc le ventirad est proche. Il ne peut pas être plus grand car il doit partager l'espace arrière avec les sorties de la carte mère. Le plus grand ventilateur de 14cm tournant à 900 tr/min est situé sur la façade avant et va aspirer de l'air extérieur pour l'injecter dans le boitier. En tournant plus rapidement le plus petit ventilateur va permettre d'avoir un débit comparable au plus grand, cela permet d'avoir un équilibre entre l'air aspiré et extrait du boitier pour obtenir une ventilation optimale.
context_page_description: A computer fan is any fan inside, or attached to, a computer case used for active cooling. Fans are used to draw cooler air into the case from the outside, expel warm air from inside and move air across a heat sink to cool a particular component. Both axial and sometimes centrifugal fans are used in computers. Computer fans commonly come in standard sizes, and are powered and controlled using 3-pin or 4-pin fan connectors.
context_section_description: Fans are used to move air through the computer case. The components inside the case cannot dissipate heat efficiently if the surrounding air is too hot. Case fans may be placed as intake fans, drawing cooler outside air in through the front or bottom of the chassis (where it may also be drawn over the internal hard drive racks), or exhaust fans, expelling warm air through the top or rear. Some ATX tower cases have one or more additional vents and mounting points in the left side panel where one or more fans may be installed to blow cool air directly onto the motherboard components and expansion cards, which are among the largest heat sources.
  Standard axial case fans are 40, 60, 80, 92, 120, 140, 200 and 220 mm in width and length. As case fans are often the most readily visible form of cooling on a PC, decorative fans are widely available and may be lit with LEDs, made of UV-reactive plastic, and/or covered with decorative grilles. Decorative fans and accessories are popular with case modders. Air filters are often used over intake fans, to prevent dust from entering the case and clogging up the internal components. Heatsinks are especially vulnerable to being clogged up, as the insulating effect of the dust will rapidly degrade the heatsink's ability to dissipate heat.
caption: Fans from computer case – front and back
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