The document discusses the basics of a cathode ray oscilloscope. It describes how an oscilloscope works by using an electron gun to shoot a focused beam of electrons at a fluorescent screen, allowing the shape of an electrical signal to be displayed as the beam is swept back and forth by deflector plates. It also lists the main components of an oscilloscope including the cathode ray tube, vertical and horizontal amplifiers, time base generator, and trigger circuit. Finally, it provides some examples of how oscilloscopes can be used to analyze electrical signals.

2. VIPUL POPHALE
RATNESH SAHU
RAGHURAJ SINGH DODIYA
SANDEEP KUMAR GUPTA

4. CATHO
RAY
DE

5. INTRODUCTION:
•
Oscilloscope is an very
important test instrument in
electrical and electronics field.
•
It is used to look at the 'shape'
of electrical signals by
displaying a graph of voltage
against time on its screen.
•
It is like a voltmeter with the
valuable extra function of
showing how the voltage
varies with time.

6. CATHODE RAY OSCILLOSCOPE
 Popular instrument to show time,
voltage both DC and AC. Shows Volts
/ Time.
 Display waveforms. Spectrum scope shows volts to
Frequency
 Cathode (-ve ) is heated, emits
electrons,
 accelerated toward a (+ve)
fluorescent screen. Intensity grid, Focus
grid, Accelerating anode. (Electron gun)
6

7.  An oscilloscope a
device that displays a
graph of an electrical
signal. the vertical (Y)
axis represents voltage
and the horizontal (X)
axis represents time.
The intensity or
brightness of the
display is sometimes
called the Z axis.
WHAT IS AN OSCILLOSCOPE ?

8. History of CRO >>
The earliest mode of creating
an image of waveform was
through a labourious and
painstaking process. This was
known as Hand-
drawn Oscilloscope..
In the late 19 century , CRT were
developed, then with the help of
crt “Karl Ferdinand Braun”
invented the first crt
oscilloscope by applying an

9. Power Supply Unit
Cathode Ray Tube
Vertical Amplifier
Horizontal Amplifier
Time Base Generator(Sweep Generato
Trigger Circuit
Delay Line

11. BASIC CATHODE RAY TUBE :
The CRT uses an evacuated glass envelope which is large, deep,
heavy, and relatively fragile.

12.  Electron gun

13.  Deflection system

14.  Fluorescent screen

15. VERTICAL AMPLIFIER >>
HORIZONTAL AMPLIFIER >>

16. TIME BASE GENERATOR >>

17. TRIGGER CIRCUIT >>
<< DELAY LINE:

19. From figure
V1T = V1 sin θ1,
V2T = V2 sin θ2
But V1T = V2T
V1 sin θ1 = V2 sin θ2
Or V2/V1 = sin θ1 / sin θ2
This the reason why focussing system in
CRT is termed as “ ELECTRON LENS ”

20. The pre-accelerating and accelerating anodes are connected to the same
potential while focussing anode is connected to lower potential.
On account of potential difference between focussing and 2 accelerating
anodes ,a non-uniform field exists on each of 2 ends of focussin g anode . The
surfaces thus form, “ DOUBLE CONCAVE LENS ”.

21. D= SldEd
2dEa S=Distance between screen and centre Of
deflecting plates
Ed=Potential between deflecting plates
ld=Length of deflecting plates
d=Distance between deflecting plates
Ea=Voltage of pre-accelerating anode

24. Control The Brightness By Controlling Electron Flow

25. To focus the electron into narrow beams on the
screen.

26. Accelerates the electron

27.  Electron beam:

28. Working Principle:
It basically works on the amplifier and triggering
networks.

29. O/P Power
Screen
Intensity
Focus
Volt/Div
Time/Div
Channel

30. Panel Function
VOLTS/DIV Select the vertical deflection factor of the CRT display
TIME/DIV Select the horizontal deflection factor of the CRT display
INTEN (Intensity) Control The INTEN (intensity) control (sometimes called BRIGHTNESS) adjusts the brightness
of the beam on the CRT. The control is rotated in a clockwise direction to increase the
intensity of the beam and should be adjusted to a minimum brightness level that is
comfortable for viewing.
FOCUS and ASTIG The FOCUS control adjusts the beam size. The ASTIG (astigmatism) control adjusts
(Astigmatism) Controls the beam shape. The FOCUS and ASTIG controls are adjusted together to produce a
small, clearly defined circular dot
TRACE ROTATION The TRACE ROTATION control allows for minor adjustments of the horizontal portion
Control of the trace so that you can align it with the horizontal lines on the graticule.
BEAM FINDER Control When pushed, the BEAM FINDER pulls the beam onto the screen so that you can use
the horizontal and vertical POSITION controls to center the spot.
Horizontal and Vertical The horizontal and vertical POSITION controls are used to position the trace. Because
POSITION Controls the graticule is often drawn to represent a graph, some oscilloscopes have the
positioning controls labeled to correspond to the X and Y axes of the graph. The X axis
represents horizontal movement; the Y axis represents the vertical movement.
AC-GDN-DC AC- Ac Signal
GDN - grounding the signal
DC- Dc Signal

31. APPLICATIONS OF OSCILLOSCOPES:
• 1. Ac & Dc voltage measurement.
• 2. Measurement of the voltage between two
points on the waveform
• 3. Elimination of undesired signal components
• 4. Time measurements
• 5. Time difference measurements
• 6. Pulse width measurements
• 7. Pulse risetime and falltime measurements
• 8. Phase difference measurements
• 9. Frequency measurements
• 10. Relative measurements
• 11. Sweep multiplication (magnification)
• 12. Application of x-y operation