Skip to main content

Crystal Oscillator

Crystal Oscillator

  • The cryatals are either naturally occuring or synthetically manufuctured, exhibiting the piezoelectric effect means under the influence of the mechanical pressure, the voltage gets generated across the opposite faces of the crystal

    • Crystal

  • If the mechanical force is applied in such a way to force the crystal to vibrate, the a.c voltage get generated across it. Conversely, if the crystal is subjected to a.c voltage, it vibrates causing mechanical distortion in the crystal shape.
  • Every crystal has its own resonating frequency depending on its cut. So under the influence of the mechanical vibrations, the crystal generates an electrical signal of very constant frequency. The crystal has a greater stability in holding the constant frequency
  • A crystal oscillator is basically a tuned-circuit oscillator using a piezoelectric crystal as its resonant tank circuit. The crystal oscillator are preferred when greater frequency stability required. Hence the crystals are used in watches, communication transmitters and recivers etc
    • Pierce oscillator using crystal
  • The main sustances exhibiting the piezoelectric effect are quartz Rochelle salt and taurmaline.
  • Rochelle salt have the greatest piezoelectric activity. For a given a.c voltage, they vibrate more then quartz or tormaline. Hence these are preferred making microphones associated with portable tape recorders, headsets, loudspeakers etc. Rochelle salt in mechanically weakest of the three and break very easily.
  • Tourmaline shows least piezoelectric effect but mechanically strongest. The tormaline is most expensive and hence its use is rare in practice.
  • Quartz is a compromise between the piezoelectric activity of Rochelle salt and the strength of the tourmaline. Quartz is inexpensive and easily available in nature and hence very commonly used in the crystal oscillator.

Labels:

Comments

Post a Comment

Popular Post

Miller Crystal Oscillator

Miller Crystal Oscillator Miller Crystal Oscillator Similar to modifications in Colpitt's oscillator, the Hartley oscillator circuit can be modified, to get Miller crystal Oscillator In Hartley oscillator circuit, two inductors and one capacitor is required in the tank circuit. One inductor is replaced by the crystal which acts as an inductor for the frequencies slightly greater then the series resonant frequency. The tuned circuit of L1 and C is offtuned to behave as an inductor i.e. L1. The crystal behaves as other inductance L2 between base and ground. the Internal capacitance of the transistor acts as a capacitor required to fullfill the elements of the tank circuit The crystal decides the operating frequency of the oscillator.
Post a Comment
Read more

Electronic oscillator division types and use

Electronic oscillator division types and use Electronic oscillator division types and use Introduction to oscillator An oscillator is a amplifier and it is a close loop circuit or network. It uses the Positive feedback. It is not require the externel signel and generate the a desired frequency A oscillatpr acts like generator, It oscillates the constant amplitude and frequency. Oscillator can generate the frequency upto gigahertz. Classification of the Oscillators Oscillators are classified based on the type of waveforms generate from the oscillator, range, frequency, parameters used. Based on Output waveforms. Based on circuit components. Range of operating frequency. Based on feedback uses or not uses Types of oscillatprs LC Oscillator Har...
Post a Comment
Read more