Oscillator na Tsawon RC

Oscillator RC Phase Shift

Oscillator RC phase shift ya zama fitaccen kabilu mai sana'ar da ta yi amfani da tashar-resistor-capacitor (RC) don bincike rarraba shaida da take daidaita.

Oscillators RC phase-shift sun amfani da tashar-resistor-capacitor (RC) (Figure 1) don bayyana phase-shift da ke bukatar shi daga feedback signal. Suna da kyau a cikin frequency stability kuma zai iya bayyana sine wave mai tsari zuwa yankin daɗi na loads.

Idan an tabbata, tashar RC mai tsawo ana haske output wanda ya fi input da 90 o.

A gaba, farkon fasaa yana da yawan da ita ce saboda hali na capacitor da ba da ma'adan. Farkon fasaa na tashar RC an fara a cikin nau'in kimiyya a matsayin

Amsa, X C = 1/(2πfC) shine reactance na capacitor C kuma R shine resistor. A oscillators, wasu kafin RC phase-shift networks, kowane take bayyana phase-shift da ya fi, za su iya cascaded don in bayyana phase-shift condition led by the Barkhausen Criterion.

Wanda shi ne misal na musamman shine maimakon da oscillator RC phase-shift ta form shi da cascading three RC phase-shift networks, kowane take bayyana phase-shift da 60o, kamar yadda a nuna Figure 2.

A nan, collector resistor RC ya hada collector current na transistor, resistors R 1 and R (nearest to the transistor) suna da voltage divider network kuma emitter resistor RE ya jagoranci kyautar. Ba ni, capacitors CE and Co suna da emitter by-pass capacitor and the output DC decoupling capacitor, respectively. Kuma, circuit ya nuna three RC networks employed in the feedback path.

Hakan ya haɗa output waveform ya shiga 180o a lokacin da ta yi shiga daga output terminal zuwa base na transistor. Ba ni, wannan signal zai shiga 180o ta hanyar transistor a cikin circuit saboda farkon fasaa daga input zuwa output zai 180o a cikin common emitter configuration. Wannan ya haɗa net phase-difference ta 360o, don in bayyana phase-difference condition.

Wace karamin haka da za su iya bayyana phase-difference condition shine amfani da four RC networks, kowane take bayyana phase-shift da 45o. Saboda haka, za a iya kammala cewa oscillators RC phase-shift suna da hukuma da suke a yi a cikin hukuma saboda babban number of RC networks in them is not fixed. Amma, ya kamata a lura, idan an yi karɓe a stages, zai haɗa frequency stability na circuit, amma zai haɗa output frequency na oscillator saboda loading effect.

Generalized expression for the frequency of oscillations produced by a RC phase-shift oscillator is given by

Amsa, N shine number of RC stages formed by the resistors R and the capacitors C.

Ba ni, kamar yadda aka samun da most type of oscillators, even the RC phase-shift oscillators can be designed using an OpAmp as its part of the amplifier section (Figure 3). Nevertheless, the mode of working remains the same while it is to be noted that, here, the required phase-shift of 360 o is offered collectively by the RC phase-shift networks and the Op-Amp working in inverted configuration.

Frequency na RC phase-shift oscillators zai iya zama da gang-tuning, kafin an yi kawo da capacitors, kuma resistors suna daidai. Ba ni, idan an yanayin RC phase-shift oscillators da LC oscillators, zai iya tabbatar da cewa, na biyu ya amfani da manyen kabilu masu aiki da na uku. 

Saboda haka, output frequency produced from the RC oscillators can deviate much from the calculated value rather than in the case of LC oscillators. Nevertheless, they are used as local oscillators for synchronous receivers, musical instruments and as low and/or audio-frequency generators.