Editing Computer fan control (section)

==== Integrated or discrete linear regulators ====
[[File:Samsung NC10 - motherboard - SMSC EMC2102-93150.jpg|thumb|SMSC EMC2102 rotational-speed-based fan controller with hardware thermal  shutdown]]
Common voltage regulator ICs like the popular LM78xx series are sometimes used to provide variable or constant voltage to fans. When thermally bonded to the computer's chassis, one of these ICs can provide up to 1&nbsp;A of current at a voltage of 6, 8, 9 or 10&nbsp;V for the LM7806, LM7808, LM7809 and LM7810, respectively.<ref>{{cite web|url=https://www.fairchildsemi.com/products/power-management/voltage-regulators/positive-voltage-linear-regulators/LM7808.html|title=LM7808|work=fairchildsemi.com|access-date=2014-08-13|archive-url=https://web.archive.org/web/20150402112751/https://www.fairchildsemi.com/products/power-management/voltage-regulators/positive-voltage-linear-regulators/LM7808.html|archive-date=2015-04-02|url-status=dead}}</ref> Adjustable versions like the popular [[LM317]] also exist; when combined with a [[potentiometer]], these adjustable regulators allow the user to vary the fan speed of several fans at currents far in excess of what a standard potentiometer could handle.<ref>{{cite web|url=http://www.ti.com/product/lm317|title=LM317 - Single Channel LDO - Linear Regulator (LDO) - Description & parametrics|work=ti.com}}</ref>

For higher currents, discrete linear regulators are relatively simple to construct using a power transistor or [[MOSFET]] and a small signal transistor or a Zener diode as a voltage reference. While discrete regulators require additional components (a minimum of two transistors, three resistors and a small capacitor), they allow for arbitrarily high currents, allowing for the regulation of additional fans and accessories.

As with other linear regulators, the waste heat that is produced will be roughly {{math|1=''P'' {{=}} (''V''<sub>in</sub> - ''V''<sub>out</sub>) ''I''<sub>out</sub>}}.<ref>{{Cite web |url=https://www.exar.com/common/content/document.ashx?id=1225 |title=Thermal Considerations for Linear Regulators  |date=November 28, 2006 |access-date=2015-02-26 |archive-url=https://web.archive.org/web/20150402105439/https://www.exar.com/common/content/document.ashx?id=1225 |archive-date=2015-04-02 |url-status=dead }}</ref>