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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Learn about electronics Oscillators. An electrical dual of the standard Pierce oscillator using two inductors and one capacitor is equivalent to the Hartley oscillator.

Sinusoidal Oscillators Colpitts Oscillator

Advantages of Colpitts oscillator. A Colpitts oscillator, invented in by American engineer Edwin H.

The Colpitts topology grounds the node where C1 and L1 meet in the circuit diagrams shown above: As owcillator result, these oscillators can be tuned either by varying their inductance or the capacitance. Therefore, points 1 and 2 are out of phase by o. Then the cycle will begin again, with the current flowing in the opposite direction through the inductor.

The capacitor C 1 has its one end connected to base via C c and the other to emitter via C e. Feedback to the base of transistor is taken from the junction of Capacitor C2 and inductor L1 in the tank circuit. All types of electronic oscillators oscillahor their input voltage to control the oscillation frequency. The frequency of oscillations of the Colpitts oscillator can be determined using the equation below. The inverting amplifier provides lscillator phase shift to take the total around the loop to degrees, and provides enough gain to cancel the attenuation through the two low-pass stages.


Both capacitors act as delay elements in low-pass filter stages: Cavity oscillator Delay-line oscillator Opto-electronic oscillator Robinson oscillator Transmission-line oscillator Klystron oscillator Cavity magnetron Gunn oscillator. The energy lost in the tank circuit is compensated by the transistor and the oscillations are sustained. A Colpitts oscillator is the electrical dual of a Hartley oscillatorwhere the feedback signal is taken from an “inductive” voltage divider consisting of two coils in series or a tapped coil.

Voltage across C2 is phase opposite to that of the voltage across the C1 and it is colpjtt voltage across C2 that is fed back to the transistor. The Colpitts oscillator can be realized using valves, transistors, FETs or op-amp. Electronic oscillators Electronic design.

Sine osclilator, square wave etc. For this reason the circuit is also called a tank circuit. Draw the waveform on the grid. Having built the Colpitts oscillator, coopitt on breadboard or strip board, check that the circuit is oscillating satisfactorily, then complete the measurements in Tables 1 and 2.

Webarchive template wayback links All accuracy disputes Articles with disputed statements from March Lscillator terminal 1 is at positive potential with respect to terminal 3 at any instant, then terminal 2 will be at negative potential with respect to 3 at that instant because terminal 3 is grounded. As with any oscillator, the amplification of the active component should be marginally larger than the attenuation of the capacitive voltage divider, to obtain stable operation.

Module 2.4

The effective capacitance and the inductance form a bandpass filter that is very sharp at the frequency of interest, allowing the amplifier to build up oscillations at that oscilaltor. From this, it can be noted that, in this case, the gain of the circuit is less dependent on the circuit elements of the tank circuit. Trade-Offs in Analog Circuit Design: In the circuit diagram resistors R1 and R2 gives a voltage divider biasing to the transistor.


The presence of coupling capacitor C c in the output circuit does not permit the dc currents to go to the tank circuit the flow of dc current in a tank circuit reduces its Q. During this process, the electrostatic energy stored in the capacitor gets converted into magnetic flux oscollator in turn is stored within the inductor in the form of electromagnetic energy.

The Colpitts Oscillator Explained | Hackaday

Notify me of new posts via email. However they can also be designed to produce oscillations in the low audio-frequency range. As the name implies, linear oscillators are used to produce linear or sinusiodal waveforms. RF Sine Wave Oacillator 3.

The Colpitts Oscillator Explained

Thus, a Colpitts oscillator used as a variable-frequency oscillator VFO performs best when a variable inductance is used for tuning, as opposed to tuning one of the two capacitors. If the two capacitors are replaced by inductors, and magnetic coupling is ignored, the oscilltor becomes a Hartley oscillator.

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