Editing Soldering iron (section)

=== Temperature-controlled soldering iron ===
[[File:Ersadur.svg|thumb|Section of a soldering iron tip with an internal heating element]]
Simple soldering irons reach a temperature determined by thermal equilibrium, dependent upon power input and [[cooling]] by the environment and the materials it comes into contact with. The iron temperature will drop when in contact with a large mass of metal such as a chassis; a small iron will lose too much temperature to solder a large connection.  More advanced irons for use in electronics have a mechanism with a temperature sensor and method of temperature control to keep the tip temperature steady; more power is available if a connection is large. Temperature-controlled irons may be free-standing, or may comprise a head with heating element and tip, controlled by a base called a soldering station, with control circuitry and temperature adjustment and sometimes display.

A variety of means are used to control temperature. The simplest of these is a variable power control, much like a [[light dimmer]], which changes the equilibrium temperature of the iron without automatically measuring or regulating the temperature. Another type of system uses a [[thermostat]], often inside the iron's tip, which automatically switches power on and off to the element. A thermal sensor such as a [[thermocouple]]  may be used in conjunction with [[Electronic circuit|circuitry]] to monitor the temperature of the tip and adjust power delivered to the heating element to maintain a desired temperature.<ref name="winstanley"/><ref>{{cite web|url=https://www.electromaker.io/blog/article/what-is-the-ts100-soldering-iron|title=What is the TS100 Soldering Iron?}}</ref> In some models, the firmware for the control circuitry is [[free software]] that can be modified by the end-user.<ref name="hackaday.com">{{cite web|url=https://hackaday.com/2017/07/24/review-ts100-soldering-iron/|title=Review: TS100 Soldering Iron|date=24 July 2017}}</ref><ref>{{cite web|url=https://hackaday.com/2017/07/07/tetris-on-a-soldering-iron/|title=Tetris on a Soldering Iron|date=7 July 2017}}</ref><ref>{{cite web|url=https://www.vice.com/en/article/play-the-tiniest-version-of-tetris-on-a-soldering-iron/|title=Play the Tiniest Version of 'Tetris' on a Soldering Iron|date=7 July 2017}}</ref>

Another approach is to use magnetized soldering tips which lose their magnetic properties at a specific temperature, the [[Curie point]]. As long as the tip is magnetic, it closes a switch to supply power to the heating element. When it exceeds the design temperature it opens the contacts, cooling until the temperature drops enough to restore magnetisation. More complex Curie-point irons circulate a high-frequency AC current through the tip, using magnetic physics to direct heating only where the surface of the tip drops below the Curie point.<ref name="curiepointsolderingiron">{{cite web|url=http://www.thermaltronics.com/tmt-9000s.php|title=Thermaltronics Soldering: Products > TMT-9000S Soldering and Rework Station|website=Thermaltronics.com|access-date=27 August 2018}}</ref>