Help to students

1. WEL COME

2. KARNATAKA VETERINARY ANIMALAND FISHERIES SCIENCES UNIVERSITY BIDAR
DAIRY SCIENCE COLLGE, KALABURAGI
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3. TOPIC
CATHODE RAY OSCILLOSCOPE
Course no. :- DE311
Course Title:- Instrumentation and process control
Credit Hours:- 3(2+1)
Presented To
Dr. Adarsh M Kalla
Asst. Professor
Dept. of Dairy Engineering
Presented By
Prakash
DGK2212
3rd
year 1st
Semester
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4. CONTENT
• INTRODUCTION
• BLOCK DAIGRAM
• CONSTRUCTION
• WORKING
• APPLICATION
• ADVANTAGES
• DISADVANTAGES
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5. INTRODUCTION
• The cathode ray oscilloscope is an electronic test
instrument
• It is used to obtain waveforms when the different input
signals are given.
• The oscilloscope observes the changes in the electrical
signals over time, thus the voltage and time describe a
shape and it is continuously graphed beside a scale.
• By seeing the waveform, we can analyze some
properties like amplitude, frequency, rise time,
distortion, time interval, etc.
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6. Block Diagram of CRO
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7. Block Diagram of CRO
The Vertical Amplifier block amplifies the weak signals so that they produce
measurable deflection on the screen; this amplifier decides the sensitivity and
bandwidth of the CRO. Its output is given as input to the delay line.
The delay line: The delay line block adds a small delay to the signal before it
reaches the horizontal deflection plates. This helps avoid distortion on the screen
caused by the signal reaching the plates at different times.
Trigger Circuit: This circuit generates trigger pulses that keep the
synchronization between the input signal and the horizontal deflection circuit.
The time-based generator creates sawtooth waveforms for the horizontal
deflection plates, allowing calibration of the CRO in terms of time.
A horizontal amplifier boosts the sawtooth signal from a time-based generator
for the horizontal plates. 7

8. Working principle
• A CRO (Cathode Ray Oscilloscope) works by using a high- speed electron beam
that is deflected by an electric or magnetic field to produce a visual display of an
electrical signal.
• When the electrical signal is applied to the two deflection plates to produce
electric fields perpendicular to each other.
• The electron beam is deflected by these fields, causing it to hit a phosphorescent
screen, producing a bright spot.
• The position of the spot on the screen represents the magnitude and waveform of
the electrical signal.
• By measuring the position of the spot, the frequency, amplitude, and waveform of
the signal can be determined.
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9. The construction of CRO
Cathode Ray Tube
• Converts electrical signals into visual signals.
• Contains electrostatic deflection plates and an electron gun.
• Horizontal and vertical deflections are independent actions, moving the ray across
the monitor.
 Electron Gun Assembly
• Emits electrons to form rays.
• Key components include a heater, grid, cathode, and anodes for acceleration and
focus.
• Strontium and barium layers at the cathode enhance electron emission at low
temperatures.
• Electrons flow through a co-axial along the CRT’s axis into a control grid.
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10. The construction of CRO
 Deflecting Plate
• Consists of vertical (Y plate) and horizontal (X plate) deflecting plates.
• Controls the electron ray direction after leaving the electron gun.
 Fluorescent Screen
• Flat faceplate about 100 mm by 100 mm; larger screens are curved.
• Made by molding molten glass with an inner coating of phosphor crystals.
• Fluorescence occurs when electron rays strike phosphor crystals, producing light.
 Glass Envelope
• Conical and evacuated structure.
• Inside faces are covered with aquadag, a conductive material.
• Assists the electrons by connecting to the accelerating anode.
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11. APPLICATIONS
It is used in huge applications like radio stations for observing the transmitting &
receiving the properties of the signal.
It is used to measure the voltage, current, frequency, inductance, admittance,
resistance, and power factor.
This device is also used to check the AM and FM circuits characteristics
This device is used to monitor the signal properties as well as characteristics and
also controls the analog signals.
The shape of voltage and current waveform can be observed by CRO.
Used for comparing phase & frequency
To check the reactions of nervous and heartbeat.
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12. ADVANTAGES
Training requirements
Consistency & quality
Time efficiency
Expertise & experience
Capacity for problem-solving
Voltage measurement
Current measurement
Examination of waveform
Measurement of phase and frequency
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13. DISADVANTAGES
These oscilloscopes are expensive as compared with other measuring devices
like multimeters.
They are complicated to repair once it gets damaged.
These devices need complete isolation
These are huge, heavy and uses more power
A lot of control terminals which is not so easy to understand at one instance But
for easy of use.
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14. Conclusion
In conclusion, the cathode ray oscilloscope (CRO) is a versatile and essential
tool for visualizing and analyzing electrical signals.
 It utilizes a cathode ray tube (CRT) to display a visual representation of voltage
changes over time, making it indispensable in electronics and related fields.
Reference:
o https://www.elprocus.com
o https://www.geeksforgeeks.org
o http://testbook.com
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15. THANK YOU