A key switch (sometimes called a keyswitch or lock switch) is a key-operated switch. Key switches are used in situations where access to the switch's functions needs to be restricted.
Key switches are available as components with solder connections, and are available with a variety of ampere ratings. They may use tubular or other specially-shaped keys for extra security.
Key switches have been used for a variety of purposes, up to and including the launch of nuclear missiles.
In less secure applications such as corridor and restroom lighting controls in public buildings, tamper-resistant switches with a simpler key mechanism may be used instead.
Wikimedia Commons has media related to Key switches.References
Martston, R. M. (1998-07-15). Security Electronics Circuits Manual. Newnes. ISBN 978-0-08-093854-7. 978-0-08-093854-7 ↩
Safety), Center for Chemical Process (2017-01-06). Guidelines for Safe Automation of Chemical Processes. John Wiley & Sons. ISBN 978-1-119-35189-4. 978-1-119-35189-4 ↩
Schum, John L. (1988). Electronic Locking Devices. Butterworths. ISBN 978-0-409-90125-2. 978-0-409-90125-2 ↩
"Key switches". Maplin Electronics. Retrieved 23 August 2014. http://www.maplin.co.uk/c/components/switches/key-switches ↩
"Simulation of a Peacekeeper missile launch". Defence Imagery. Retrieved 23 August 2014. http://dodimagery.afis.osd.mil/imagery.html#a=search&s=simulation%20of%20a%20Peacekeeper%20Missile%20Launch&t=0&guid=0f307fd0b6d2c847b0c0e2dcbaac7a20a6f6a092 ↩
"Low-Cost Security Measures for School Facilities" (PDF). National Clearinghouse for Educational Facilities. Retrieved 1 September 2014. http://www.ncef.org/pubs/low_cost_measures.pdf ↩
"Product Bulletin for 30 Amp AC Toggle Switches". Leviton. Retrieved 1 September 2014. http://www.leviton.com/OA_HTML/ibcGetAttachment.jsp?cItemId=xreQ9kM.SwSAGa6JaqTCzw ↩