Crystal Oscillator Circuit

The crystal usually quartz has a high degree of stability in holding con stant at whatever frequency the crystal is originally cut to operate.

Crystal oscillator circuit.

Typical colpitts transistor crystal oscillator circuit. The crystal oscillator circuit like this get popular uses in digitals. Reduced crystal voltage limits above 1 mhz 20 4 5. Load impedance across the crystal terminals 18 4 3.

1 crystal oscillator circuit using 74ls04. 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. Thus it utilizes the vibrating crystal s mechanical resonance which is made with a piezoelectric material for generating an electrical signal of a. For example sine wave triangular waveform and square wave.

Circuit design characteristics 4 1. In crystal oscillators the usual electrical resonant circuit is replaced by a mechanically vi brating crystal. 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. Crystal s internal series resistancer 17 4 2.

They generate the frequencies to be a base time. 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. The oscillators or frequency generators provide a waveform out in various forms. Dc biasing of transistor and ic amplifier stages 21 4 6.

Generally 8mhz crystal oscillator is used in microprocessors and microcontrollers. Oscillator loop gain 19 4 4. The basic components used in the circuit. Crystal response to a step input13 4.

This functions the popular pierce oscillator configuration. 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. When a voltage source is applied to a small thin piece of quartz crystal it begins to change shape producing a characteristic known as the piezo electric effect. 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.

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. The crystal oscillators are therefore used whenever great stability is needed for example in communication trans mitters and. The equivalent electrical circuit also represents the crystal action of the crystal. Hence quartz crystal oscillator circuits are superior compared to other resonators such as lc circuits turning forks and so on.

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