Oscillator Colpitts: Me kana? (Diagramma Cikin Zabe & Yadda Ake Farko Tsari na Oscillator Colpitts)

Wani shine Colpitts Oscillator?

A Colpitts Oscillator wani abu na LC oscillator. An Colpitts oscillators suka samu a shekarar 1918 tare da mafi girman malamin Amurka Edwin H. Colpitts. Daga cikin manyan LC oscillators, Colpitts oscillators suna amfani da kungiyoyi na inductors (L) da capacitors (C) don gina oscillation a wata frequency. Abin da ya kawo Colpitts oscillator shi shine cewa feedback ta aiki ya fara daga voltage divider mai biyu na capacitors a nan yi series a kan inductor.

Zan iya ce... yana nuna da yake fitaccen.

Saboda haka za a duba circuit ta Colpitts oscillator don fahimtar tushen yadda wannan yake haɗa.

Circuit ta Colpitts Oscillator

Figure 1 tana bayyana Colpitts oscillator na tank circuit. A inductor L tana ci parallel da serial combination ta capacitors C1 da C2 (a nan an nuna da red enclosure).

Abubuwan da suke cikin circuit tana daidaiwa da cewa common-emitter CE, wanda ake bias da voltage divider network, i.e., RC shine collector resistor, RE shine emitter resistor wanda ake amfani da ita don stabilize circuit, da resistors R1 da R2 suke ci voltage divider bias network.

Kuma, capacitors Ci da Co su ne input da output decoupling capacitors sannan emitter capacitor CE shine bypass capacitor wanda ake amfani da ita don bypass amplified AC signals.

Idan power supply tana ci ON, transistor tana bude, tana zama collector current IC saboda haka capacitors C1 da C2 tana ci charged. Idan suka samu charged da suka fi sani, suka bude tun inda inductor L.

A nan, electrostatic energy wanda ake tsara a capacitor tana ci magnetic flux, wanda ake tsara a inductor a kan electromagnetic energy.

Kuma, inductor tana bude, wanda tana charge the capacitors har sai. Kafin haka, cycle tana ci, wanda tana ba oscillations a tank circuit.

Kafin haka, figure tana nuna cewa output of the amplifier tana ci C1 kuma tana ci-phase with the tank circuit’s voltage and makes-up for the energy lost by re-supplying it.

Daga baya, voltage feedback to the transistor tana samu across the capacitor C2, wanda tana mean feedback signal tana out-of-phase with the voltage at the transistor by 180o.

Wannan shine saboda voltages developed across the capacitors C1 da C2 su ne opposite in polarity as the point where they join is grounded.

Kafin haka, this signal tana ci additional phase-shift of 180o by the transistor wanda tana result in a net phase-shift of 360o around the loop, satisfying the phase-shift criterion of Barkhausen principle.

Frequency ta Colpitts Oscillator

A nan, circuit tana iya haɗa da oscillator producing sustained oscillations by carefully monitoring the feedback ratio given by (C1 / C2). Frequency ta such a Colpitts Oscillator depends on the components in its tank circuit and is given by

Where the Ceff is the effective capacitance of the capacitors expressed as