How does a Clapp oscillator work?

The Clapp oscillator is much like a Colpitts oscillator with the capacitive voltage divider producing the feedback signal. The addition of a capacitor C3 in series with the inductor L1 results in the difference in the two designs and distinguishes the Clapp Oscillator from the Colpitts and Hartley configurations.

What is the main difference between Hartley and Colpitts oscillator?

Thus the main difference between a Colpitts Oscillator and a Hartley Oscillator is that the former uses tapped capacitance, while the latter uses tapped inductance. Colpitts oscillator is generally used in RF applications and the typical operating range is 20KHz to 300MHz.

Why Clapp oscillator is preferred over the Colpitts oscillator?

But in a Clapp oscillator, the transistor and stray capacitances have no effect on capacitor C3, so the oscillation frequency is more stable and accurate. This is the reason that Clapp oscillator is preferred over a Colpitt’s oscillator.

What is Colpitts oscillator?

The Colpitts oscillator can be realized using valves, transistors, FETs or op-amp. It is much similar to the Hartley oscillator except the addition of tank circuit. In Colpitts oscillator the tank circuit consists of two capacitors in series and an inductor connected in parallel to the serial combination.

How do you calculate the effective capacitance of a Colpitts oscillator?

If C1 and C2 are the individual capacitance, then the effective capacitance of the serial combination C= (C1C2)/ (C1+C2). By using ganged variable capacitors in place of C1 and C2, the Colpitts oscillator can be made variable.

What is the use of L1 in a Colpitts oscillator?

L1 represents the self inductance of the coil. It is used for generation of sinusoidal output signals with very high frequencies. The Colpitts oscillator using SAW device can be used as the different type of sensors such as temperature sensor.

What is the gain of an op-amp based oscillator?

The gain of the opamp based oscillator can be individually set using the components Rf and R1 and it is a great advantage. The gain of an inverting op-amp amplifer is given by the equation; A = -Rf/R1.