lab18--5/5(Electronics and Oscilloscope)

This is the square mode on oscilloscope

This is the CRT, which is an important part of the oscilloscope.

It is possible to prove  that the deflection of an electron passing between charged metal plates is proportional to the voltage across the plates.  It is this proportional relationship between voltage and deflection that allows us to use an oscilloscope to display voltage changes graphically.

Inside the CRT there is an electron gun. The electrons go every direction, and a vertical deflation plate, horizontal deflation plate.

We predict the line on oscilloscope will jump vertically by some time if we apply 1.2 V battery on vertical deflation

a pair of parallel plates with voltage V across them will have a uniform electric field between them of magnitude E=V/d

1.An electron,q is placed in an E field E. what is the expression for F on the electron in terms of charge q, electrical field E?

F=qE

2.IF the mass is m, what is the acceleration?

ma=qE=qV/d

a=qV/(md)

3. Assume that the uniform electric field between the plates is in the y-direction.  Show that if the initial velocity, v0x, is in the x-direction, it remains constant as the electron moves perpendicular to the electric field so that vx = v0x.

4.d. If the plates have a length L, what is the time it takes an electron moving at an initial velocity v0x to pass between them?

t=L/V

v=at=qVL/(mdVx)

What is the distance electron travels during this time?

The work is shown below

Producing voltage change for input to a scope:

1 function generator

1 small speaker

1 BNC to clip lead cable

 Turn function generator on to DC offset

Activity:sounds from function generator

1,Describe the sound you hear when you have the wave output set at 96HZ

It sounds like deep horn

2. Describe what happens to the sound s when you use triangle and square wave output instead

Square sounds deeper and louder than triangle

3. What will happen if you change the frequency of the function generator?

Sounds change to higher if we set it smaller than 96hz

4. How do change in Amplitude affect the sounds?

the larger the amplitude, the louder sound

Activity: the oscilloscope controls

1.Play with the intensity control and the power/illumination controls. What do they do?

intensity larger makes line brighter

voltage change causes line to shift upward

2. Use the intensity control to adjust the brightness of the spot on the oscilloscope screen so that it is just comfortably visible. Play with the focus control what do they do?

Focus makes graph blurred or sharper

3. play with the time base control. what does it do?

turn Time base control will make the line shift upward(?)

 Activity :Measuring changing voltage

1. With the function generator set to 96 hz, Use your oscilloscope to determine the period of the sin wave form

5.5ms*2=11*10^-3 s

2.How does this period compare with he period calculated on the basis of the frequency reading on the dial?

f=1/t=1/(11*10^-3)=90HZ

it is 95HZ on dial

3.Experiment with DC offset control on the function generator and the AC DC  button on the oscilloscope. Explain how these controls affect the oscilloscope display

The display becomes a straight horizontal line switching to DC mode

4.switch over to the sin wave and square wave outputs of the function generator . Take a picture of each form for  your blog

Square form:

Triangle form:

5.Experiment with the freq dial and multiplier on the function generator and the time base control on the oscilloscope. How do changes in these settings affect the wave form?

When we decrease the freq dial, line becomes longer

Mystery box:

 8.5V

 5V

8V