Editing Synchro (section)

== Uses ==
Synchro systems were first used in the control system of the [[Panama Canal]] in the early 1900s to transmit lock gate and valve stem positions, and water levels, to the control desks.<ref>
{{cite book|title=The Panama Canal; An Engineering Treatise. A Series Of Papers Covering In Full Detail The Technical Problems Involved In The Construction Of The Panama Canal - Geology, Climatology, Municipal Engineering; Dredging, Hydraulics, Power Plants, Etc. Prepared By Engineers And Other Specialists In Charge Of The Various Branches Of The Work And Presented At The International Engineering Congress, San Francisco, California|url=https://archive.org/details/panamacanalanen00goetgoog|year=1916|author=Goethals, George W|publisher=McGraw Hill|location=New York}}
</ref>

[[Image:Synchro-connections.jpg|thumb|View of the connection diagram of a synchro transmitter]]
[[Fire-control system]] designs developed during [[World War II]] used synchros extensively, to transmit angular information from guns and sights to an [[Analog computer|analog fire control computer]], and to transmit the desired gun position back to the gun location. Early systems just moved indicator dials, but with the advent of the [[amplidyne]], as well as motor-driven high-powered hydraulic [[Servomechanism|servos]], the fire control system could directly control the positions of heavy guns.<ref>[http://www.eugeneleeslover.com/USNAVY/CHAPTER-10-D.html "Naval Ordnance and Gunnery, Volume 1", 1957, U.S. Navy Manual, Chapter 10.]</ref>

Smaller synchros are still used to remotely drive indicator gauges and as rotary position sensors for aircraft control surfaces, where the reliability of these rugged devices is needed. Digital devices such as the [[rotary encoder]] have replaced synchros in most other applications. 

Selsyn motors were widely used in [[motion picture]] equipment to synchronize [[movie camera]]s and [[sound recording]] equipment, before the advent of [[crystal oscillators]] and [[microelectronics]].

Large synchros were used on naval warships, such as destroyers, to operate the steering gear from the wheel on the bridge.