Build the Colpitts oscillator shown using either breadboard (proto board) or strip board, then test the oscillator’s operation using a multi meter and oscilloscope. The Colpitts Oscillator is a particularly good circuit for producing fairly low distortion sine wave signals in the RF range, 30kHz to 30MHz. Colpitts oscillator working, circuit diagram and theory. Colpitts oscillator frequency equation. Colpitts oscillator using transistor and opamp.

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The the inductor starts discharging and capacitors gets charged again.

Colpitts oscillator

R C is the collector resistor, R E is the emitter resistor which is used to stabilize the circuit and the resistors R 1 and R 2 form the voltage divider bias network. Learn about electronics Oscillators. This is also an important circuit when a crystal is part of the feedback circuit instead of an inductor. The two series capacitors C 1 and C 2 form the potential divider used for providing the feedback voltage — the voltage developed across capacitor C 2 provides the regenerative feedback required for sustained oscillations.

Cavity oscillator Delay-line oscillator Opto-electronic oscillator Robinson oscillator Transmission-line oscillator Klystron oscillator Cavity magnetron Gunn oscillator. This approximate result also applies to oscillators employing different active device, such as MOSFETs and vacuum tubes. Both capacitors act as delay elements in low-pass filter stages: Draw the waveform on the grid. But remember that a larger output voltage will also mean a higher collector current.

The Colpitts Oscillator Explained

Notify me of new posts via email. The equation for frequency is also the same. Phase-shift oscillator Twin-T oscillator Wien bridge oscillator. Eventually all the charge on the capacitor will be gone and the voltage across it will reach zero.


Leave a Reply Cancel reply Enter your comment here Next, the inductor starts to discharge which charges the capacitors once again.

Colpitts Oscillator

However they can also be designed to produce oscillations in the low audio-frequency range. Capacitors C1, C2 and coliptt L1 forms the tank circuit. Colpitts Oscillator An oscillator is used to produce electronic signal with oscillating periods.

As a result the equation for frequency can be simplified as. The radio frequency choke R. Clapp oscillator Clap volpitt is just a modification of Colpitts oscillator.

Design an amplifier if you want an oscillator! Here the voltage across C 1 provides feedback. During this process, the electrostatic energy stored in the capacitor gets converted into magnetic flux which in turn is stored within the inductor in the form of electromagnetic energy. However they can even be used for microwave applications as their capacitors provide low reactance path for the high-frequency signals. This oacillator in better frequency stability as well as a better sinusoidal output waveform.

Butler oscillator Pierce oscillator Tri-tet oscillator. Further, the capacitors C i and C o are the input and output decoupling capacitors while the emitter capacitor C E is the bypass capacitor used to bypass the amplified AC signals.

A Colpitts oscillatorinvented in by American engineer Edwin H. If the two capacitors are replaced by inductors, and magnetic coupling is ignored, the circuit becomes a Hartley oscillator. Periodic oscillation starts for a critical bias current and with the variation of the bias current to a higher value chaotic oscillations are observed.


When they are fully charged they starts discharging through the inductor L1. The main purpose of adding this additional capacitor C3 is to improve the frequency stability.

The frequency determining network is a parallel resonant circuit which consists of colpitt capacitors C 1 and C 2 along with an inductor L.

Sinusoidal Oscillators Colpitts Oscillator

This kind of circuit osciolator almost analogous to that of the one explained earlier. This value should be sufficient to overcome any positive resistance in the circuit. The output of the phase-shift L-C network is coupled from the junction of L and C 2 to the amplifier input at base through coupling capacitor C Cwhich blocks dc but provides path to ac.

Oscillators are broadly classified into two — linear oscillators and non-linear oscillators.

Figure 2 shows such a Colpitts oscillator which uses an Op-Amp in inverting configuration in its amplifier section while the tank circuit remains similar to that in the case of Figure 1. Feedback to the base of transistor is taken from the junction of Capacitor C2 and inductor L1 in the tank circuit.

Note how some values produce different amplitudes or better wave shapes. Hons All rights reserved.

He also builds the circuit and looks at the real world performance. Further, this signal is provided with an additional phase-shift of o by the transistor which results in a net phase-shift of o around the loop, satisfying the phase-shift criterion of Barkhausen principle.