Ece Lab Exp2

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COLLEGE OF ENGINEERING

Electronics Engineering Department

OSCILLOSCOPE Experiment no. 2

ECE 322N-1F; 1:30-4:30

Lanag, Rodney Jay E. Engr.Handig

20081126752 Professor

Date performed: July 07, 2010

Date Submitted: July 28, 2010

GRADE



THEORETICAL DISCUSSION

A n oscilloscope (also known as a scope, CRO or, an O-scope) is a type of electronic test

instrument that allows observation of constantly varying signal voltages, usually as a two-dimensionalgraph of one or more electrical potential differences using the vertical or 'Y' axis, plotted as a function

of time, (horizontal or 'x' axis). A lthough an oscilloscope displays voltage on its vertical axis, any other

quantity that can be converted to a voltage can be displayed as well. In most instances, oscilloscopes

show events that repeat with either no change or change slowly.

Oscilloscopes are commonly used to observe the exact wave shape of an electrical signal. In

addition to the amplitude of the signal, an oscilloscope can show distortion, measure frequency, the

time between two events (such as pulse width or pulse rise time) and relative timing of two related

signals. Some oscilloscopes can analyze and display the frequency spectrum of a repetitive event.

These are called spectrum analyzers, and depending on the analyzer, can display spectra from audio

frequency well into the Gigahertz range.

Oscilloscopes are used in the sciences, medicine, engineering, and telecommunications

industry. General-purpose instruments are used for maintenance of electronic equipment and

laboratory work. Special-purpose oscilloscopes may be used for such purposes as analyzing an

automotive ignition system, or to display the waveform of the heartbeat as an electrocardiogram.

Originally all oscilloscopes used cathode ray tubes as their display element and linear amplifiers

for signal processing, (commonly referred to as CROs) however, modern oscilloscopes have LCD or

LED screens, fast analog-to-digital converters and digital signal processors. A lthough not as

commonplace, some oscilloscopes used storage CRTs to display single events for a limited time.

Oscilloscope peripheral modules for general purpose laptop or desktop personal computers use the

computer's display, allowing them to be used as test instruments.



DISPLAY AND APPEARANCE

The basic oscilloscope is typically divided into four sections: the display, vertical controls,

horizontal controls and trigger controls. The display is usually a CRT or LCD panel which is laid out with

both horizontal and vertical reference lines referred to as the graticule. In addition to the screen, most

display sections are equipped with three basic controls, a focus knob, an intensity knob and a beam

finder button.

I.CALIBRATION

1. Oscilloscope Screen

Oscilloscopes have an x axis and a y axis. The x axis is horizontal and

represents time in seconds (s). The y axis is vertical and represents voltage in

volts (v).

2. First, set all of the buttons and switches to their normal positions. This means, all push button

switches should be in the out position, all slide switches in the up position, all rotating dials are

centered, and the TIME/DIV and VOLTS/DIV and the HOLD OFF are in the Calibrated (C A L) position.

3. Time-Div

Set the VOLTS/DIV to 1V/DIV.

4. Set the TIME/DIV control to 2s/DIV

5. Switch the power to ON. You should now see the trace moving across the screen.

6. Y-Position Control

Locate the Y-POS control. This will allow you to move the trace up or down the screen.

A djust the trace so that it runs horizontally across the center of the screen.

7. Now locate the INTENSITY and FOCUS controls. These will allow you to control how bright the trace

is and whether it is sharp or blurry.



8 . Time/Div Control

The TIME/DIV will control the horizontal scale of the graph. A s you change

this setting to a smaller number, the trace will move across the screen faster.

9. The VOLTS/DIV control will determine the vertical scale of the graph. Set

the control to where you can see the entire vertical motion on the screen.

EXPERIMENTAL RESULTS/DATA

II. AC VOLTAGE MEASUREMENT

Transformer

Output

Measured

Voltage

3V 8.96V

6V 17.98V

9V 26.4V

12V 35.4V

III. SIGNAL & FREQUENCY & AMPLITUDE MEASUREMENT

FunctionGeneral

Frequency

MeasuredFrequency

Period( )

1kHz 1.176Hz 0.85

10kHz 6.932kHz 0.14

100kHz 97.09kHz 0.01

1MHz 961.5kHz 0.00104



SQUARE WAVE

SINE WAVE

Function General

A mplitude

Measured

A mplitude

10% 1.84V

20% 3.52V

50% 9.44V

75% 18.4V

100% 32.2V

FunctionGeneral

A mplitude

Measured A mplitude

10% 1.04V

20% 3.6V

50% 9.8V

75% 16.6V

100% 25.8V



GRAPHS:

1 kHz 100 kHz

10 kHz 1 MHz

Sine Wave(1 unit: 1)

10 %

20 %



50 %

75 %

100 %



Square Wave(1 unit: 1)

10 %

20 %

50 %

75 %



100 %



EXPERIMENTAL DISCUSSION




display sections are equipped with three basic controls, a focus knob, an intensity knob and a beam

finder button.

The vertical section controls the amplitude of the displayed signal. This section carries a Volts-

per-Division (Volts/Div) selector knob, an A C/DC/Ground selector switch and the vertical (primary) input

for the instrument. A dditionally, this section is typically equipped with the vertical beam position knob.

The horizontal section controls the time base or ³sweep´ of the instrument. The primary control

is the Seconds-per-Division (Sec/Div) selector switch. A lso included is a horizontal input for plotting

dual X-Y axis signals. The horizontal beam position knob is generally located in this section.

The trigger section controls the start event of the sweep. The trigger can be set to automatically

restart after each sweep or it can be configured to respond to an internal or external event. The

principal controls of this section will be the source and coupling selector switches. A n external trigger

input (EXT Input) and level adjustment will also be included.

CONCLUSION

Based on our experiment, an engineering student must know how to manipulate analog and

digital oscilloscope because when we are already in our fields, we don¶t know what of those two are will

going to use.

In order to do the experiment, the team work of the group is very significant at all times,

because if there is teamwork, the possibility of determining the data¶s will achieve very fast.

RECOMMENDATION

In this experiment, I recommend that in order to make our work faster in getting data¶s in the

oscilloscope, digital oscilloscope is much better and more efficient because the data that will going to

compute are already in the screen of it. But, as an engineering student we should be able to know howto manipulate analog and digital oscilloscope.

EXPERIMENT SUMMARY

Oscilloscopes are commonly used to observe the exact wave shape of an electrical signal. In

addition to the amplitude of the signal, an oscilloscope can show distortion, measure frequency, the

time between two events (such as pulse width or pulse rise time) and relative timing of two related

signals. Some oscilloscopes can analyze and display the frequency spectrum of a repetitive event.



These are called spectrum analyzers, and depending on the analyzer, can display spectra from audio

frequency well into the Gigahertz range.




display sections are equipped with three basic controls, a focus knob, an intensity knob and a beamfinder button.



GLOSSARY

O scilloscope - is a type of electronic test instrument that allows observation of constantly varying signal

voltages.

X-axis - is the horizontal axis of a two-dimensional plot in Cartesian coordinates that is conventionally

oriented to point to the right (left figure). In three dimensions, the x-, y-, and z- are usually arranged so

as to form a right-handed coordinate system.

Y -axis - is the vertical axis of a two-dimensional plot in Cartesian coordinates. Physicists and

astronomers sometimes call this axis the ordinate, although that term is more commonly used to refer

to coordinates along the y-axis.

Voltage - is a short name for the electrical force that would drive an electric current between thosepoints.

- is the total energy required to move a small electric charge along that path, divided by themagnitude of the charge.

Graticule - is a transparent scale in front of a cathode-ray oscilloscope or other measuring instrument.

Cathode -ray tube - is a vacuum tube that produces images when its phosphorescent surface is struckby electron beams.

Frequency - is the number of waves that pass a fixed point per unit time; also, the number of cycles or

vibrations undergone in unit time by a body in periodic motion.

LCD (Liquid -Crystal display) - is a low-power flat-panel display used in many laptop computers,

calculators and digital watches, made up of a liquid crystal that is sandwiched between layers of glass

or plastic and becomes opaque when electric current passes through it.

LED (light -emitting diode) - A semiconductor diode that converts electric energy intoelectromagnetic radiation at a visible and near infrared frequencies when its pn junction isforward biased.

Spectrum Analyzer - is a test instrument used to show the distribution of energy contained in the

frequencies emitted by a pulse magnetron; also used to measure the Q of resonant cavities and lines,

and to measure the cold impedance of a magnetron.



REFERENCES:

Answers.com

http://mathworld.wolfram.com/y-Axis.html

http://mathworld.wolfram.com/x-Axis.html

http://www.ehow.com/how_4526145_calibrate-an-oscilloscope.html

http://en .w ikipedia .org

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Ece Lab Exp2