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Can someone tell me what the exact differences are between the Pierce and the Colpitts oscillator?

I've read in wikipedia that the Pierce oscillator is a derivative of the Colpitts oscillator, but I am not sure what the difference is and what advantages we have when we move from Colpitts to Pierce.

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The Colpitts, Pierce and Clapp oscillators comprise ...

  • a resonant circuit consisting of two series capacitors and an inductive element (an inductor, or a crystal, ceramic, MEMs or series LC resonator operating on the inductive side of resonance)
  • an amplifier arranged around it to maintain oscillation

The main distinguishing point about the Pierce oscillator is that it has the mid-point of the capacitors grounded. This allows the amplifier to be a two-port inverting type like a logic inverter gate, ideal for integration with logic devices, rather than a three terminal device like a transistor that needs biassing.

A Colpitts oscillator always uses an inductor. When operated with a resonator in the inductor position, it's called a Clapp oscillator.

Both Colpitts and Clapp oscillators can be arranged with different terminals grounded, so the transistor is used in 'common base', 'common collector', or 'common emitter', with the first two appearing to be more popular.

There are incidental differences in the use of the oscillator types. Fine frequency/phase stability of a logic clock is not often required, so the amplitude control of a Pierce clock is done by allowing it to slam against the rails, giving it poor power supply and amplitude noise rejection. A radio receiver OTOH needs quiet signals, and will use a transistor biassed so that it goes into emitter cutoff each cycle, far quieter than the alternatives.

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  • \$\begingroup\$ In some places, I've seen that colpitts oscillator use only LC components and transistors only. Whereas, pierce oscillator do not use inductors and they make use of a quartz crystal. So, the colpitts oscillator does not use a crystal? \$\endgroup\$
    – user220456
    Jun 30, 2022 at 7:55
  • \$\begingroup\$ @Newbie You can use a Colpitts with a more general inductive element, though then it would tend to be called a Clapp oscillator. \$\endgroup\$
    – Neil_UK
    Jun 30, 2022 at 7:58
  • \$\begingroup\$ Oh, is there any other difference other than the one mentioned in your answer? \$\endgroup\$
    – user220456
    Jun 30, 2022 at 7:59
  • \$\begingroup\$ @Newbie OK, I've tightened up the logic of the answer. \$\endgroup\$
    – Neil_UK
    Jun 30, 2022 at 8:10
  • \$\begingroup\$ Thank you for the answer. I've accepted the answer! \$\endgroup\$
    – user220456
    Jun 30, 2022 at 8:14

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