Editing Electronic oscillator (section)

==Relaxation oscillator==
{{Main|Relaxation oscillator}}

[[File:OpAmpHystereticOscillator.svg|thumb|A popular [[op-amp]] [[Relaxation oscillator#Comparator–based electronic relaxation oscillator|relaxation oscillator]].]]

A '''nonlinear''' or '''[[relaxation oscillator]]''' produces a non-sinusoidal output, such as a [[Square wave (waveform)|square]], [[sawtooth wave|sawtooth]] or [[triangle wave]].<ref name="Garg" /><ref name="Graf">{{cite book   
  | last = Graf
  | first = Rudolf F. 
  | title = Modern Dictionary of Electronics
  | publisher = Newnes
  | date = 1999
  | pages = 638
  | url = https://books.google.com/books?id=uah1PkxWeKYC&pg=PA638
  | isbn = 0750698667}}</ref><ref name=" Morris">{{cite book   
  | last =  Morris
  | first = Christopher G. Morris
  | title = Academic Press Dictionary of Science and Technology
  | publisher = Gulf Professional Publishing
  | date = 1992
  | pages = 1829
  | url = https://books.google.com/books?id=nauWlPTBcjIC&pg=PA1829
  | isbn = 0122004000 }}</ref><ref name="Du">{{cite book   
  | last = Du
  | first = Ke-Lin
  |author2=M. N. S. Swamy 
  | title = Wireless Communication Systems: From RF Subsystems to 4G Enabling Technologies
  | publisher = Cambridge Univ. Press
  | date = 2010
  | pages = 443
  | url = https://books.google.com/books?id=5dGjKLawsTkC&q=%22relaxation+oscillator&pg=PA443
  | isbn = 978-1139485760}}</ref> It consists of an energy-storing element (a [[capacitor]] or, more rarely, an [[inductor]]) and a nonlinear switching device (a [[Latch (electronics)|latch]], [[Schmitt trigger]], or [[negative resistance]] element) connected in a [[feedback loop]].{{sfn|Gottlieb|1997|p=69-73}}<ref name="HyperPhysics">{{cite web
  | last = Nave
  | first = Carl R.
  | title = Relaxation Oscillator Concept
  | work = HyperPhysics
  | publisher = Dept. of Physics and Astronomy, Georgia State Univ.
  | date = 2014
  | url = http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/relaxo.html
  | accessdate = February 22, 2014}}</ref> The switching device periodically charges the storage element with energy and when its voltage or current reaches a threshold discharges it again, thus causing abrupt changes in the output waveform.<ref name="van der Tang">{{cite book
  | last1  = van der Tang
  | first1 = J.     
  | last2  = Kasperkovitz
  | first2 = Dieter
  | last3  = van Roermund
  | first3 = Arthur H.M.
  | title = High-Frequency Oscillator Design for Integrated Transceivers
  | publisher = Springer Science and Business Media 
  | date = 2006
  | location = 
  | pages = 20
  | language = 
  | url = https://books.google.com/books?id=0rniokw7bLkC&dq=%22ring+oscillator%22+oscillator+relaxation&pg=PA20
  | archive-url= 
  | archive-date=
  | doi = 
  | id = 
  | isbn = 0306487160
  | mr = 
  | zbl = 
  | jfm =}}</ref>{{rp|p.20}}  Although in the past negative resistance devices like the [[unijunction transistor]], [[thyratron]] tube or [[neon lamp]] were used,{{sfn|Gottlieb|1997|p=69-73}} today relaxation oscillators are mainly built with [[integrated circuits]] like the [[555 timer IC]].

Square-wave relaxation oscillators are used to provide the [[clock signal]] for [[sequential logic]] circuits such as timers and [[digital counter|counters]], although [[crystal oscillator]]s are often preferred for their greater stability.<ref name="Patrick">{{cite book
  | last1  = Patrick
  | first1 = Dale R.
  | last2  = Fardo
  | first2 = Stephen W.
  | last3  = Richardson
  | first3 = Ray E.
  | title = Electronic Devices and Circuit Fundamentals
  | publisher = CRC Press
  | date = 2023
  | language = 
  | url = https://books.google.com/books?id=tZK4EAAAQBAJ&pg=PT767
  | doi = 
  | id = 
  | isbn = 9781000879773
  | mr = 
  | zbl = 
  | jfm =}}</ref>{{rp|p.20.1}} Triangle-wave or sawtooth oscillators are used in the timebase circuits that generate the horizontal deflection signals for [[cathode-ray tube]]s in analogue [[oscilloscope]]s and [[television]] sets.<ref name="Patrick" />{{rp|p.20.1}} They are also used in [[voltage-controlled oscillator]]s (VCOs), [[inverter]]s and [[switching power supply|switching power supplies]], [[dual-slope ADC|dual-slope analog to digital converter]]s (ADCs), and in [[function generator]]s to generate square and triangle waves for testing equipment. In general, relaxation oscillators are used at lower frequencies and have poorer frequency stability than linear oscillators.

[[Ring oscillator]]s are built of a ring of active delay stages, such as [[inverter (logic gate)|inverter]]s.<ref name="van der Tang" />{{rp|p.20}} Generally the ring has an odd number of inverting stages, so that there is no single stable state for the internal ring voltages. Instead, a single transition propagates endlessly around the ring.

Some of the more common relaxation oscillator circuits are listed below:

*[[Multivibrator]]
*[[Pearson–Anson effect|Pearson–Anson oscillator]]
*[[Ring oscillator]]
*[[Delay-line oscillator]]
*[[Royer oscillator]]