Crystal oscillator

Mohammad Alsharafi 230

14 / 4 / 2014

WELCOME

Sinusoidal Oscillators

Electronics circuits

Transistor AMP OP AMP Timers

Sinusoidal oscillator

Crystal oscillator

Introduction

What is this device ?

Function signal generator

Why we use it in the lap?to give us a wave that we can adjust its frequency

and shape

Why we use the oscillator?to give us a wave that we can adjust its frequency

and shapeWhat is the different between

them ?

What is the different between function generator & oscillator circuit?

Discuss about the answer as partner for 5 min.

Partner work

Stability effects

• Temperature :

Rising of Temperature will change the frequency (f) and the gain (A).

To avoid this issue we should use a heat sink.

Oscillator stability

• Voltage source :

The value of voltage source is not stable by time, so the frequency will change.

By using a voltage regulator the voltage will not change, and so is

frequency.

Oscillator stability

• The load:

When we change the load the frequency will change.

To solve this problem we should put a buffer between the oscillator and the load .

Oscillator stability

• The quality factor (Q) :

• To have an accurate oscillator, the Q should be between 104 and 106.

• To have this number of Q, the impedance of the capacitor and inductor should be very small, and that is impassible.

To avoid this problem we should connect a crystal between the output and noninverter input of the oscillator

circuit.

Crystals

Topaz

Sucrose

Quartz

Berlinite

TourmalineWhat is special about these crystals?

Piezoelectric effect

• piezoelectricity means voltage resulting from pressure, or vibration resulting from voltage.

• There are thousands of application stand on this effect (such as cigarette lighter) .

video

Exercise 1

• Why we use a crystal in the oscillator circuit?

To have an accurate oscillator.

• What is special about some crystals we use them in electronics ?

The piezoelectric effect .

Part 1

Exercise

• What is piezoelectric effect ?

voltage resulting from pressure, and vibration resulting from voltage.

Exercise

• We use voltage regulator in the oscillator circuit to ……………….. .

D. Avoid Changing in voltage source.

Part 2

B. Avoid The heat.C. Avoid Changing in the load.

A. Have an accurate oscillator.

Exercise

• What is the best value of the quality factor that will makes an accurate oscillator.

D. 107

B. 103

C. 104

A. 105

Exercise

• The man on the video talked about the error of the crystal oscillator, so that error is……. .

D. Nothing correct. (what is the answer?)

B. One minute per two years.C. 3 minutes per 3 years.

A. One minute per a month.

Crystal Oscillator

Topaz

Sucrose

Quartz

Berlinite

Tourmaline

Quartz• Quartz is the second most abundant mineral in

the Earth's continental crust.

• It is made up of SiO4 silicon–oxygen tetrahedra.

• There are many kind of quartz.

Quartz oscillator

• Quartz oscillator is as like as any other electronics component.• It has symbol and different values.• Its values start from a few kilo Hertz to hundreds of hertz.

symbol equivalent circuit

Exercise 2

Group of 3

Each group will do the task In the whiteboard for 5 min

• Draw the symbol and the equivalent circuits of the quartz oscillator.

Crystal oscillator

Mohammad Alsharafi 230

14 / 4 / 2014

THANK

YOU