Crystal Oscillator Circuit

The oscillators or frequency generators provide a waveform out in various forms.

Crystal oscillator circuit.

Load impedance across the crystal terminals 18 4 3. Crystal response to a step input13 4. Oscillator loop gain 19 4 4. Generally 8mhz crystal oscillator is used in microprocessors and microcontrollers.

The applied electric field will produce a mechanical deformation across some materials. The inverter is biased into a linear amplifying mode by r1 and the crystal is linked amongst the input and the output of the circuit by means of tc1. The crystal oscillators are therefore used whenever great stability is needed for example in communication trans mitters and. Circuit design characteristics 4 1.

The crystal oscillator circuit will be designed to present this capacitance to the crystal. In crystal oscillators the usual electrical resonant circuit is replaced by a mechanically vi brating crystal. The basic components used in the circuit. Reduced crystal voltage limits above 1 mhz 20 4 5.

It is quite possible to employ a single inverter to deliver the basis of a crystal oscillator and such a circuit appears in diagram below. Most of this will be made up by the two capacitors c1 and c2 although the remaining elements of the circuit will provide some capacitance. To obtain a very high level of oscillator stability a quartz crystal is generally used as the frequency determining device to produce another types of oscillator circuit known generally as a quartz crystal oscillator xo. To control an electronic circuit.

This frequency is often used to keep track of time as in quartz wristwatches to provide a stable clock signal for digital integrated circuits and to stabilize frequencies for radio transmitters. 1 crystal oscillator circuit using 74ls04. Crystal s internal series resistancer 17 4 2. Typical colpitts transistor crystal oscillator circuit.

A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a precise frequency. This functions the popular pierce oscillator configuration. The equivalent electrical circuit also represents the crystal action of the crystal. For example sine wave triangular waveform and square wave.

Dc biasing of transistor and ic amplifier stages 21 4 6. Thus it utilizes the vibrating crystal s mechanical resonance which is made with a piezoelectric material for generating an electrical signal of a. The crystal usually quartz has a high degree of stability in holding con stant at whatever frequency the crystal is originally cut to operate. They generate the frequencies to be a base time.

The crystal oscillator circuit usually works on the principle of the inverse piezoelectric effect.