Snmek 1

Anglicky v odbornch pedmtech"Support of teaching technical subjects in EnglishEducational program: Mechanic - electrician

Title of program: Technical trainingII. classOscillators controlled by crystalWorked out: Bc. Chumchal Miroslav

Projekt Anglicky v odbornch pedmtech, CZ.1.07/1.3.09/04.0002je spolufinancovn Evropskm socilnm fondem a sttnm rozpotem esk republiky.

Scheme of crystal, equivalent connectionControl circuit of the oscillatorScheme with serial resonance of the crystal Scheme with a parallel resonance of the crystalCharacteristic of oscillators controlled by crystalStudents activities

Oscillators controlled by crystal

Schematic mark of the crystal

Equivalent scheme of the crystal

The controlled circuit of the oscillator controlled by crystal made up a desk from quartz crystal.It is equipped with plaster and with outlets in opposite sides.The size of crystal is chosen so that mechanical resonance frequency is the same as a frequency of electric oscillators which the oscillator should generate.The crystal behaves like a resonance system.

Controlled circuit of the oscillator

With serial resonance of the crystal

Oscillators controlled by crystal

S paraleln rezonanc krystalu Oscillators controlled by crystal

6Courses of frequency characteristics showing, that crystal behaves like a resonance system which serial resonance on frequency fs and parallel on frequency fp. Oscillators controlled by crystal used one or second frequency.

Advantage of the crystal oscillators is bigger stability of frequency in compare with RC oscillators or LC oscillators. It is used like a source of exact frequency in measure devices or in a digital clock too.

Characteristics of oscillators controlled by crystal

Explain function of the oscillator controlled by crystalWhich material is used in a crystal produce?Explain the difference between oscillator controlled by crystal with serial resonance and parallel resonance of crystal.Draw the course of a modular and phase frequency characteristic of crystal impedance.

Students activities- checking questions

Build up an oscillator controlled by crystal on a contact field with parallel resonance.Measure a frequency on which an oscillator resonance.

Practical students activities

Vlastn poznmkov seitElektronika pro 3.ronk SP elektrotechnickch. V. Rek, P. Mdel. Vydalo Nakladatelstv technick literatury Praha 1989. ISBN 80-03-00102-1 Literature used