study of cathode ray oscilloscope experiment theory

Cathode-Ray Oscilloscope

WARNING:    Never advance the Intensity Control so far that an excessively bright spot appears. Bright spots imply burning of the screen. A sharp focused spot of high intensity (great brightness) should never be allowed to remain fixed in one position on the screen for any length of time as damage to the screen may occur.

• NOC:Experimental Physics III (Video) 
• Co-ordinated by : IIT Kharagpur
• Available from : 2019-11-13
• Intro Video
• Lecture 1 : Basic Tools and Instruments in the Laboratory
• Lecture 2 : Basic Tools and Instruments in the Laboratory (Contd.)
• Lecture 3 : Cathode Ray Oscilloscope (CRO)
• Lecture 4 : Cathode Ray Oscilloscope (CRO (Contd.)
• Lecture 5 : Electro Magnet and Constant Current Power Supply
• Lecture 6 : Electro Magnet and Constant Current Power Supply (Contd.)
• Lecture 7 : Electro Magnet and Constant Current Power Supply (Contd.)
• Lecture 8 : Gaussmeter/Teslameter
• Lecture 9 : Gaussmeter/Teslameter (Contd.)
• Lecture 10 : Lock in Amplifier
• Lecture 11 : Lock in Amplifier (Contd.)
• Lecture 12 : Measurement of magneto resistance
• Lecture 13 : Magneto resistance for Semiconductor
• Lecture 14 : Hall Effect
• Lecture 15 : Hall Effect as a function of magnetic Field
• Lecture 16 : Hall Effect as a function of temperature
• Lecture 17 : To study the variation of resistivity of metal and semiconductor at low temperature region (Contd.)
• Lecture 18 : To study the variation of resistivity of metal and semiconductor at low temperature region (Contd.)
• Lecture 19 : Measurement of magnetisation of ferromagnetic material
• Lecture 20 : Measurement of magnetisation of ferromagnetic material (Contd.)
• Lecture 21: Susceptibility of paramagnetic substance by Quincke's tube method
• Lecture 22: Experiment of Quincke's Tube Method
• Lecture 23: Susceptibility of paramagnetic substance by Gouy's method
• Lecture 24: Dielectric constant of solid
• Lecture 25: Dielectric constant of non - conducting liquid
• Lecture 26: P - E Loop of Ferroelectric Material
• Lecture 27: Measurement of Ionic Conductivity
• Lecture 28: Measurement of Ionic Conductivity (Contd.)
• Lecture 29: Electron Spin Resonance (ESR)
• Lecture 30: Electron Spin Resonance (ESR) Experiment
• Lecture 31: Superconductivity
• Lecture 32: Superconductivity (Contd.)
• Lecture 33: Superconductivity (Contd.)
• Lecture 34: Nuclear g-factor
• Lecture 35: Nuclear g-factor (Contd.)
• Lecture 36: P-N Junction
• Lecture 37: P-N Junction (Contd.)
• Lecture 38: P-N Junction (Contd.)
• Lecture 39 : Zeeman Effect
• Lecture 40 : Zeeman Effect (Contd.)
• Lecture 41 : Zeeman Effect (Contd.)
• Lecture 42 : Sodium Yellow Doublet
• Lecture 43 : Sodium Yellow Doublet (Contd.)
• Lecture 44 : Study of Absorption Spectrum of Iodine Vapour
• Lecture 45: Study of Absorption Spectrum of Iodine Vapour (Contd.)
• Lecture 46: Study of Absorption Spectrum of Iodine Vapour (Contd.)
• Lecture 47: Determination of Wavelength of Spectral Lines using Constant Deviation Spectrometer
• Lecture 48: Determination of Wavelength of Spectral Lines using Constant Deviation Spectrometer (Contd.)
• Lecture 49: Photoelastic Property of Materials
• Lecture 50: Photoelastic Property of Materials (Contd.)
• Lecture 51: Photoelastic Property of Materials (Contd.)
• Lecture 52: Faraday Effect
• Lecture 53: Faraday Effect (Contd.)
• Lecture 54: Electron Diffraction
• Lecture 55: Electron Diffraction (Contd.)
• Lecture 56: Determination of Velocity of Light in Free Space
• Lecture 57: Determination of Velocity of Light in Free Space (Contd.)
• Lecture 58: X - Ray Diffraction and Crystal Structure
• Lecture 59: X - Ray Diffraction and Crystal Structure (Contd.)
• Lecture 60: X - Ray Diffraction and Crystal Structure (Contd.)
• Lecture 61: X - Ray Diffraction and Crystal Structure (Contd.)
• Lecture 62:
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Video Transcript:

What is a CRO (Cathode Ray Oscilloscope) & Its Working

The CRO stands for a cathode ray oscilloscope . It is typically divided into four sections which are display, vertical controllers, horizontal controllers, and Triggers. Most of the oscilloscopes are used the probes and they are used for the input of any instrument. We can analyze the waveform by plotting amplitude along with the x-axis and y-axis. The applications of CRO are mainly involved in the radio, TV receivers, also in laboratory work involving research and design. In modern electronics, the CRO plays an important role in the electronic circuits .

What is a CRO?

The cathode ray oscilloscope is an electronic test instrument , it is used to obtain waveforms when the different input signals are given. In the early days, it is called as an Oscillograph. 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, and etc.

Block Diagram of CRO

The following block diagram shows the general-purpose CRO contraction . The CRO recruits the cathode ray tube and acts as a heat of the oscilloscope. In an oscilloscope, the CRT produces the electron beam which is accelerated to a high velocity and brings to the focal point on a fluorescent screen.

Thus, the screen produces a visible spot where the electron beam strikes with it. By detecting the beam above the screen in reply to the electrical signal, the electrons can act as an electrical pencil of light which produces a light where it strikes.

To complete this task we need various electrical signals and voltages. This provides the power supply circuit of the oscilloscope. Here we will use high voltage and low voltage. The low voltage is used for the heater of the electron gun to generate the electron beam. A high voltage is required for the cathode ray tube to speed up the beam. The normal voltage supply is necessary for other control units of the oscilloscope.

The horizontal and vertical plates are placed between the electron gun and the screen, thus it can detect the beam according to the input signal. Just before detecting the electron beam on the screen in the horizontal direction which is in X-axis a constant time-dependent rate, a time base generator is given by the oscillator. The signals are passed from the vertical deflection plate through the vertical amplifier. Thus, it can amplify the signal to a level that will be provided the deflection of the electron beam.

If the electron beam is detected in the X-axis and the Y-axis a trigger circuit is given for synchronizing these two types of detections. Hence the horizontal deflection starts at the same point as the input signal.

Working Principle

The CRO working principle depends on the electron ray movement because of the electrostatic force. Once an electron ray hits a phosphor face, then it makes a bright spot on it. A Cathode Ray Oscilloscope applies the electrostatic energy on the electron ray from two vertical ways. The spot on the phosphor monitor turns due to the effect of these two electrostatic forces which are mutually perpendicular. It moves to make the necessary waveform of the input signal.

Construction of Cathode Ray Oscilloscope

The construction of CRO includes the following.

Cathode Ray Tube

Electronic gun assembly, deflecting plate.

• Fluorescent Screen For CRT
• Glass Envelop

The CRO is the vacuum tube and the main function of this device is to change the signal from electrical to visual. This tube includes the electron gun as well as the electrostatic deflection plates. The main function of this electron gun is used to generate a focused electronic ray that speeds up to high frequency.

The vertical deflection plate will turn the ray up & down whereas the horizontal ray moved the electrons beams from the left side to the right side. These actions are autonomous from each other and thus the ray may be located anyplace on the monitor.

The main function of the electron gun is to emit the electrons to form them into a ray. This gun mainly includes a heater, a grid, cathode, and anodes like accelerating, pre-accelerating & focusing. At the cathode end, the strontium & barium layers are deposited to obtain the high electrons emission of electrons at the moderate temperature, the layers of barium, and are deposited at the end of the cathode.

Once the electrons are generated from the cathode grid, then it flows throughout the control grid that is generally a nickel cylinder through a centrally situated co-axial by the axis of CRT. So, it controls the strength of the generated electrons from the cathode.

When electrons flow throughout the control grid then it accelerates with the help of a high positive potential which is applied to the pre-accelerating or accelerating nodes. The electron ray is concentrated on electrodes to flow throughout the deflection plates like horizontal and vertical & supplies on to the fluorescent lamp.

The anodes like accelerating & pre-accelerating are connected to 1500v & the focusing electrode can be connected to 500v. The electron ray can be focused on using two techniques like Electrostatic & Electromagnetic focusing. Here, a cathode ray oscilloscope utilizes an electrostatic focusing tube.

Once the electron ray leaves the electron gun then this ray will pass throughout the two sets of the deflecting plate. This set will generate the vertical deflection that is known as Y plate’s otherwise vertical deflecting plate. The set of the plate is used for a horizontal deflection which is known as X plate’s otherwise horizontal deflection.

Fluorescent Screen of CRT

In the CRT, the front face is known as the faceplate, For the CRT screen, it is flat and its size is about 100mm×100mm. The CRT screen is somewhat bent for bigger displays and the formation of faceplate can be done by pressing the molten glass into a form & after that heating it.

The inner face of the faceplate is covered by using phosphor crystal to change the energy from electrical to light. Once an electronics ray hits phosphor crystal, the energy level can be enhanced & thus light is generated throughout phosphorous crystallization, so this occurrence is known as fluorescence.

Glass Envelope

It is an extremely evacuated conical form of construction. The inside faces of the CRT among the neck as well as the display are covered through the aquadag. This is a conducting material that acts like a high-voltage electrode. The surface of the coating is connected electrically toward the accelerating anode to help the electron to be the center.

Working of CRO

The following circuit diagram shows the basic circuit of a cathode ray oscilloscope . In this, we will discuss important parts of the oscilloscope.

Vertical Deflection System

The main function of this amplifier is to amplify the weak signal so that the amplified signal can produce the desired signal. To examine the input signals are penetrated to the vertical deflection plates through the input attenuator and the number of amplifier stages.

Horizontal Deflection System

The vertical and horizontal system consists of horizontal amplifiers to amplify the weak input signals, but it is different from the vertical deflection system. The horizontal deflection plates are penetrated by a sweep voltage that gives a time base. By seeing the circuit diagram the sawtooth sweep generator is triggered by the synchronizing amplifier while the sweep selector switches in the internal position. So the trigger saw tooth generator gives the input to the horizontal amplifier by following the mechanism. Here we will discuss the four types of sweeps.

Recurrent Sweep

As the name, itself says that the sawtooth is respective that is a new sweep is started immodestly at the end of the previous sweep.

Triggered Sweep

Sometimes the waveform should be observed that it may not be predicted thus, the desired that the sweep circuit remains inoperative and the sweep should be initiated by the waveform under the examination. In these cases, we will use the triggered sweep.

Driven Sweep

In general, the drive sweep is used when the sweep is free-running but it is triggered by the signal under the test.

Non-Saw Tooth Sweep

This sweep is used to find the difference between the two voltages. By using the non-sawtooth sweep we can compare the frequency of the input voltages.

Synchronization

The synchronization is done to produce a stationary pattern. The synchronization is between the sweep and the signal should measure. There are some sources of synchronization that can be selected by the synchronization selector. Which are discussed below.

In this, the signal is measured by the vertical amplifier and the trigger is abstained by the signal.

In the external trigger, the external trigger should be present.

The line trigger is produced by the power supply.

Intensity Modulation

This modulation is produced by inserting the signal between the ground and cathode. This modulation causes by brightening the display.

Positioning Control

By applying the small independent internal direct voltage source to the detecting plates through the potentiometer the position can be controlled and also we can control the position of the signal.

Intensity Control

The intensity has a difference by changing the grid potential with respect to the cathode.

Electrical Quantities Measurements

Electrical quantities measurements by using CRO can be done like amplitude, time period and frequency.

Measurement of Amplitude

Measurement of Time Period

Measurement of frequency.

The displays like CRO is used to exhibit the voltage signal like a time function on its display. The amplitude of this signal is stable; however, we can change the number of partitions that cover up the voltage signal within vertical way by changing volt/division button on top of the CRO board. So, we will acquire the signal’s amplitude, which is there on the CRO screen with the help of the below formula.

‘A’ is the amplitude

‘j’ is the volt/division value

‘nv’ is the no. of partitions that cover up the signal within a vertical way.

CRO displays the voltage signal as a function of time on its screen. The Time period of that periodic voltage signal is constant, but we can vary the number of divisions that cover one complete cycle of the voltage signal in the horizontal direction by varying the time/division knob on the CRO panel.

Therefore, we will get the Time period of the signal, which is present on the screen of CRO by using the following formula.

‘T’ is the Time period

‘j’ is the time/division value

‘nv’ is the number of partitions that cover up one whole cycle of the periodic signal within the horizontal way.

On the CRO screen, the measurement of tile & frequency can be done very simply through the horizontal scale. If you want to make sure accuracy while measuring a frequency, then it assists to enhance the area of the signal on your CRO display so that we can more simply convert the waveform.

Initially, the time can be measured with the help of the horizontal scale on the CRO & counting the number of flat partitions from one finish of the signal to the other wherever it crosses the flat line. After that, we can develop the number of flat partitions through the time or division to discover the time period of the signal. Mathematically the measurement of the frequency can be signified as frequency = 1/period.

Basic Controls of CRO

The basic controls of CRO mainly include position, brightness, focus, astigmatism, blanking & calibration.

In the oscilloscope, the position control knob is mainly used for position control of the intense spot from the left side to the right side. By regulating the knob, one can simply control the spot from left side to the right side.

The ray’s brightness mainly depends on the intensity of the electron. The control grids are accountable for the electron intensity within the electron ray. So, the grid voltage can be controlled by adjusting the electron ray brightness.

The focus control can be achieved by regulating the applied voltage toward the center anode of the CRO. The middle & other anodes in the region of it can form the electrostatic lens. Therefore, the main length of the lens can be changed by controlling the voltage across the center anode.

Astigmatism

In CRO, this is an extra focusing control & it is analogous toward astigmatism within optical lenses. A ray is focused in the middle of the monitor would be defocused on the screen edges as the electron paths lengths are dissimilar for the center & the edges.

Blanking Circuit

The time base generator present in the oscilloscope generated the blanking voltage.

Calibration Circuit

An oscillator is necessary for the purpose of calibration within an oscilloscope. However, the oscillator which is used should generate a square waveform for preset voltage.

Applications

• The CRO’s are used in huge applications like radio stations for observing the transmitting & receiving the properties of the signal.
• The CRO 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 CRO is used through the resonance circuit to view the shape of the signal, bandwidth, etc.
• The shape of voltage and current waveform can be observed by CRO which helps to take the necessary decision in a radio station or communication station.
• It is used in laboratories for the purpose of research. Once researchers design a new circuit, then they use CRO to verify the waveforms of voltage and current of every element of the circuit.
• Used for comparing phase & frequency
• It is used in TV, Radar, and analysis of engine pressure
• To check the reactions of nervous and heartbeat.
• In the hysteresis loop, it is used to find BH curves
• Transistor curves can be traced.

The advantages of CRO include the following.

• Cost and Timeline
• Training requirements
• Consistency & quality
• Time efficiency
• Expertise & experience
• Capacity for problem-solving
• Hassle-free
• Assurance for regulatory compliance
• Voltage measurement
• Current measurement
• Examination of waveform
• Measurement of phase and frequency

Disadvantages

The disadvantages of CRO include the following.

• 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,  multiple channel capture and screen and waveform clarity one could go for Digital Storage Oscilloscope. To know more on DSO click on this link

Uses of CRO

In the laboratory, the CRO can be used as

• It can display different types of waveforms
• It can measure the short time interval
• In voltmeter, it can measure the potential difference.

In this article, we have discussed the working of CRO and its application. By reading this article you have known some basic knowledge about the working & applications of the CRO. If you have any queries regarding this article or to implement the ECE & EEE projects , please comment in the below section. Here is the question for you, what are the functions of the CRO?

Photo Credits:

• What is a CRO metroq
• Block Diagram of CRO electronicspost
• Working of CRO www.electrical4u

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EXPERIMENT MEASUREMENTS WITH A CATHODE RAY OSCILLOSCOPE

Related Papers

Ankush Verma

The paper present the function and uses of the cathode ray oscilloscope (C.R.O.).Consider a simple sine wave electrical signal from some source as in. If we can arrange things so that this sinusoidal voltage is applied to two horizontal conducting plates then in the region between these plates the electric field will be alternating with period T seconds. It will increase in strength to a maximum, decrease to zero, turn over, and increase in the opposite direction to an equal maximum, then decrease to zero again, in each period of time T. Now, if there is a beam of charged particles (electrons) streaming between these horizontal plates, the oscillating electric field there will bend the beam first up, then down, then back to the undeflected position in each time period T

Mitu Acharjee

An electron or ion gun is a scientific instrument that generates either electrons or ions, and forms them into a usable beam. The electron and ion guns built by Kimball Physics are used in a wide variety of basic research and industrial applications: from microscopic surface physics studies and semiconductor processing to large spacecraft testing. The guns range in size from about a centimeter to over half a meter long. The energy of the electrons produced also varies with the gun: from low-energy models with an energy range of 5 eV-1000 eV, to high-energy ones with an energy range of up to 100 keV. Many different kinds of ions can be produced depending on the gun, including positive ions of most gases, reactive ions, and alkali metal ions. Some guns are flood guns and produce a wide-angled beam, while others are focusable and produce a small spot. The figures below represent the overall structure of a typical, electron gun in three different ways. The first figure, A, is a three-dimensional drawing showing a cross-section of the gun. B is a plot of the electrons' paths in the gun due to the fields set up by different potentials on the gun elements; this illustrates how electron optics is similar to light optics. The third figure, C, is a schematic block diagram showing the power supplies (represented as circles) that apply voltages to the parts of the gun to produce and control the electron beam. DEFLECTION FOCUS ANODE GRID CATHODE A typical mounted Electron Gun with electrostatic focusing and deflection (EFG-7, size 0.2 X), shown with (A) a three-dimensional cross-section drawing of the electron gun, not including the mounting section, (B) a plot of the paths the electrons will take in the gun when a given set of voltages is applied to the gun elements, and (C) a block diagram with the electrical connections of the power supplies and gun elements.

Sakman Hossain

Amna Khalid

A cathode ray oscilloscope (CRO) is used to represent a waveform on an instrument and CRO provides best source as a digital instrument for representing and studying the waveforms. It can be said as an adaptation of CRT and its structure is somewhat varied for different applications; in case of television it requires a multiple beam electron gun so as to give the capability of showing different colors in the images on the TV screen.

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A modified type of secondary electron monitor useful for the monitoring of low energy electron beams during irradiation is described. Using the window foil at the end of the accelerator as a part of the detector, it is designed to have minimum disturbance on the primary beam. The monitor output is independent of the primary beam energy and proportional to the primary beam current in the range over which the monitor was tested (1.0–1.7 MeV and up to 120 μA).

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Cathode Ray Experiment

What is cathode ray tube.

A cathode-ray tube (CRT) is a vacuum tube in which an electron beam, deflected by applied electric or magnetic fields, produces a trace on a fluorescent screen.

The function of the cathode ray tube is to convert an electrical signal into a visual display. Cathode rays or streams of electron particles are quite easy to produce, electrons orbit every atom and move from atom to atom as an electric current.

Table of Contents

Cathode ray tube, recommended videos.

• J.J.Thomson Experiment

Apparatus Setup

Procedure of the experiment.

• Frequently Asked Questions – FAQs

In a cathode ray tube, electrons are accelerated from one end of the tube to the other using an electric field. When the electrons hit the far end of the tube they give up all the energy they carry due to their speed and this is changed to other forms such as heat. A small amount of energy is transformed into X-rays.

The cathode ray tube (CRT), invented in 1897 by the German physicist Karl Ferdinand Braun, is an evacuated glass envelope containing an electron gun a source of electrons and a fluorescent light, usually with internal or external means to accelerate and redirect the electrons. Light is produced when electrons hit a fluorescent tube.

The electron beam is deflected and modulated in a manner that allows an image to appear on the projector. The picture may reflect electrical wave forms (oscilloscope), photographs (television, computer monitor), echoes of radar-detected aircraft, and so on. The single electron beam can be processed to show movable images in natural colours.

J. J. Thomson Experiment – The Discovery of Electron

The Cathode ray experiment was a result of English physicists named J. J. Thomson experimenting with cathode ray tubes. During his experiment he discovered electrons and it is one of the most important discoveries in the history of physics. He was even awarded a Nobel Prize in physics for this discovery and his work on the conduction of electricity in gases.

However, talking about the experiment, J. J. Thomson took a tube made of glass containing two pieces of metal as an electrode. The air inside the chamber was subjected to high voltage and electricity flowing through the air from the negative electrode to the positive electrode.

J. J. Thomson designed a glass tube that was partly evacuated, i.e. all the air had been drained out of the building. He then applied a high electric voltage at either end of the tube between two electrodes. He observed a particle stream (ray) coming out of the negatively charged electrode (cathode) to the positively charged electrode (anode). This ray is called a cathode ray and is called a cathode ray tube for the entire construction.

The experiment Cathode Ray Tube (CRT) conducted by J. J. Thomson, is one of the most well-known physical experiments that led to electron discovery . In addition, the experiment could describe characteristic properties, in essence, its affinity to positive charge, and its charge to mass ratio. This paper describes how J is simulated. J. Thomson experimented with Cathode Ray Tube.

The major contribution of this work is the new approach to modelling this experiment, using the equations of physical laws to describe the electrons’ motion with a great deal of accuracy and precision. The user can manipulate and record the movement of the electrons by assigning various values to the experimental parameters.

A Diagram of JJ.Thomson Cathode Ray Tube Experiment showing Electron Beam – A cathode-ray tube (CRT) is a large, sealed glass tube.

The apparatus of the experiment incorporated a tube made of glass containing two pieces of metals at the opposite ends which acted as an electrode. The two metal pieces were connected with an external voltage. The pressure of the gas inside the tube was lowered by evacuating the air.

• Apparatus is set up by providing a high voltage source and evacuating the air to maintain the low pressure inside the tube.
• High voltage is passed to the two metal pieces to ionize the air and make it a conductor of electricity.
• The electricity starts flowing as the circuit was complete.
• To identify the constituents of the ray produced by applying a high voltage to the tube, the dipole was set up as an add-on in the experiment.
• The positive pole and negative pole were kept on either side of the discharge ray.
• When the dipoles were applied, the ray was repelled by the negative pole and it was deflected towards the positive pole.
• This was further confirmed by placing the phosphorescent substance at the end of the discharge ray. It glows when hit by a discharge ray. By carefully observing the places where fluorescence was observed, it was noted that the deflections were on the positive side. So the constituents of the discharge tube were negatively charged.

After completing the experiment J.J. Thomson concluded that rays were and are basically negatively charged particles present or moving around in a set of a positive charge. This theory further helped physicists in understanding the structure of an atom . And the significant observation that he made was that the characteristics of cathode rays or electrons did not depend on the material of electrodes or the nature of the gas present in the cathode ray tube. All in all, from all this we learn that the electrons are in fact the basic constituent of all the atoms.

Most of the mass of the atom and all of its positive charge are contained in a small nucleus, called a nucleus. The particle which is positively charged is called a proton. The greater part of an atom’s volume is empty space.

The number of electrons that are dispersed outside the nucleus is the same as the number of positively charged protons in the nucleus. This explains the electrical neutrality of an atom as a whole.

Uses of Cathode Ray Tube

• Used as a most popular television (TV) display.
• X-rays are produced when fast-moving cathode rays are stopped suddenly.
• The screen of a cathode ray oscilloscope, and the monitor of a computer, are coated with fluorescent substances. When the cathode rays fall off the screen pictures are visible on the screen.

Frequently Asked Questions – FAQs

What are cathode ray tubes made of.

The cathode, or the emitter of electrons, is made of a caesium alloy. For many electronic vacuum tube systems, Cesium is used as a cathode, as it releases electrons readily when heated or hit by light.

Where can you find a cathode ray tube?

Cathode rays are streams of electrons observed in vacuum tubes (also called an electron beam or an e-beam). If an evacuated glass tube is fitted with two electrodes and a voltage is applied, it is observed that the glass opposite the negative electrode glows from the electrons emitted from the cathode.

How did JJ Thomson find the electron?

In the year 1897 J.J. Thomson invented the electron by playing with a tube that was Crookes, or cathode ray. He had shown that the cathode rays were charged negatively. Thomson realized that the accepted model of an atom did not account for the particles charged negatively or positively.

What are the properties of cathode rays?

They are formed in an evacuated tube via the negative electrode, or cathode, and move toward the anode. They journey straight and cast sharp shadows. They’ve got strength, and they can do the job. Electric and magnetic fields block them, and they have a negative charge.

What do you mean by cathode?

A device’s anode is the terminal on which current flows in from outside. A device’s cathode is the terminal from which current flows out. By present, we mean the traditional positive moment. Because electrons are charged negatively, positive current flowing in is the same as outflowing electrons.

Who discovered the cathode rays?

Studies of cathode-ray began in 1854 when the vacuum tube was improved by Heinrich Geissler, a glassblower and technical assistant to the German physicist Julius Plücker. In 1858, Plücker discovered cathode rays by sealing two electrodes inside the tube, evacuating the air and forcing it between the electrode’s electric current.

Which gas is used in the cathode ray experiment?

For better results in a cathode tube experiment, an evacuated (low pressure) tube is filled with hydrogen gas that is the lightest gas (maybe the lightest element) on ionization, giving the maximum charge value to the mass ratio (e / m ratio = 1.76 x 10 ^ 11 coulombs per kg).

What is the Colour of the cathode ray?

Cathode-ray tube (CRT), a vacuum tube which produces images when electron beams strike its phosphorescent surface. CRTs can be monochrome (using one electron gun) or coloured (using usually three electron guns to produce red, green, and blue images that render a multicoloured image when combined).

How cathode rays are formed?

Cathode rays come from the cathode because the cathode is charged negatively. So those rays strike and ionize the gas sample inside the container. The electrons that were ejected from gas ionization travel to the anode. These rays are electrons that are actually produced from the gas ionization inside the tube.

What are cathode rays made of?

Thomson showed that cathode rays were composed of a negatively charged particle, previously unknown, which was later named electron. To render an image on a screen, Cathode ray tubes (CRTs) use a focused beam of electrons deflected by electrical or magnetic fields.

For more information about cathode ray experiment, the discovery of electron or other sub-atomic particles, you can download BYJU’S – The learning app. You can also keep visiting the website or subscribe to our YouTube channel for more content.

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• Cathode Ray Oscilloscope

The CRO represents a cathode ray oscilloscope. It is commonly separated into four sections which are show, vertical controllers, horizontal controllers, and Triggers- it is based on the cathode ray tubes which provide a clear image of electrical quantities. The probes that make up the majority of oscilloscopes serve as the instrument’s input. We can analyze the waveform by plotting amplitude alongside the x-axis and y-axis. The utilization of CROs is principally engaged with radio and television inputs, likewise in lab work including research and planning. The CRO plays a crucial role in the electronic circuits of modern electronics.

Table of Content

• Block Diagram
• Construction
• Applications
• Disadvantages

What is Cathode Ray Oscilloscope (CRO) ?

The cathode ray oscilloscope is an electronic test instrument, it is utilized to get waveforms when the different information signals are given. It was originally known as an oscilloscope. The oscilloscope notices the progressions in the electrical signs over the long run, subsequently the voltage and time portray a shape and it is persistently graphed close to a scale. By seeing the waveform, we can break down certain properties like amplitude, frequency, rise time, time interval, distortion, etc.

The cathode ray oscilloscope is mainly worked on voltage and additionally other actual amounts like strain, current; pressure and speed increase are changed into the voltage utilizing the transducer and show on a CRO. This instrument incorporates an iridescent spot or pointer that turns on the showcase locale because of an information voltage. This pointer can be delivered through an electron bar that hits on a fluorescent display. Basically this test is used to perform the waveforms based on the input signals or in response to them. Electron beam and cathode ray tube is used to analyze the waveforms with the help of electrical circuits and thus it plays important role in electronic circuits.

The run of the mill type of the cathode ray oscilloscope utilizes a flat info voltage i.e. inside created incline voltage known as a period. The level voltage moves the pointer occasionally in a flat manner from the passed-on side to one side on the region of the screen. Here the upward voltage is only the voltage below investigation. This voltage moves the pointer up and down on the showcase. When the info voltage moves rapidly on the showcase, then, at that point, it seems idle. Hence, this oscilloscope furnishes the imagining voltage by changing with time.

Block Diagram of Cathode Ray Oscilloscope (CRO)

The accompanying block chart shows the universally useful CRO withdrawal. The CRO is the oscilloscope’s heat source and recruits the cathode ray tube. In an oscilloscope, the CRT delivers the electron pillar which is advanced to a high speed and brings to the point of convergence on a fluorescent screen.

Block-Diagram-of-Cathode-Ray-Oscilloscope-(CRO)

Hence, the screen creates a noticeable place where the electron strikes hits with it. The electrons can behave like an electrical pencil of light and produce light where it strikes by responding to the electrical signal by detecting the beam above the screen. To get done with this responsibility we want different electrical signals and voltages. This gives the power supply circuit of the oscilloscope. Here we will utilize high voltage and low voltage. The low voltage is utilized for the radiator of the electron firearm to produce the electron beam. A high voltage is expected for the cathode ray tube to speed the beam. The typical voltage supply is important for other control units of the oscilloscope.

The level and vertical plates are put between the electron firearm and the screen, subsequently it can distinguish the shaft as indicated by the info signal. Not long prior to identifying the electron shaft on the screen in the level bearing which is in X-axis a consistent time-subordinate rate, a period base generator is given by the oscillator. The signs are passed from the upward diversion plate through the upward enhancer. In this way, it can amplifier the signal to a level that will be given the diversion of the electron beam. In the event that the electron beam is recognized in the X-axis and the Y-axis a trigger circuit is given for synchronizing these two sorts of location. Consequently, the input signal and the horizontal deflection begin at the same location.

Construction of Cathode Ray Oscilloscope

The construction of cathode ray consist of the following components:

Cathode Ray Tube

Electronic gun, deflecting plate.

• Fluorescent Screen For CRT

Glass Envelope

The CRO is the vacuum tube and the fundamental capability of this gadget is to change the sign from electrical to visual. This cylinder incorporates the electron weapon as well as the electrostatic avoidance plates. The primary purpose of this electron gun is to produce a focused, high-frequency electronic ray. The upward redirection plate will turn the beam up and down while the flat beam moved the electrons radiates from the passed on side to the right side. The ray can be positioned anywhere on the monitor because these actions are independent of one another.

The fundamental capability of the electron firearm is to transmit the electrons to frame them into a beam. This weapon for the most part incorporates a radiator, a lattice, cathode, and anodes like speeding up, per-speeding up and centering. At the cathode end, the strontium and barium layers are stored to get the high electrons outflow of electrons at the moderate temperature, the layers of barium, and are kept toward the finish of the cathode. After electrons are produced from the cathode grid, they travel through the control grid, which is typically a nickel cylinder, via a coaxial axis located in the center of the CRT. In this way, it controls the strength of the created electrons from the cathode.

At the point when electrons stream all through the control lattice then it advances with the assistance of a high certain potential which is applied to the per-speeding up or speeding up hubs. The electron beam is focused on anodes to stream all through the avoidance plates like flat and vertical and supplies on to the fluorescent light. The anodes like speeding up and per-speeding up are associated with 1500v and the centering terminal can be associated with 500v. The electron beam can be centered around utilizing two procedures like Electrostatic and Electromagnetic centering. Here, a cathode beam oscilloscope uses an electrostatic centering tube.

When the electron beam leaves the electron weapon then this beam will pass all through the two arrangements of the avoiding plate. This set will produce the upward diversion that is known as Y plate’s generally vertical diverting plate. The arrangement of the plate is utilized for a level diversion which is known as X plate’s generally even redirection.

Fluorescent Screen of CRT

In the CRT, the front face is known as the face-plate, For the CRT screen, it is level and its size is around 100mm×100mm. For larger displays, the CRT screen is slightly bent, and the face plate can be formed by pressing molten glass into a shape and then heating it.

The inward essence of the face-plate is covered by utilizing phosphor precious stone to change the energy from electrical to light. When a hardware beam hits phosphor precious stone, the energy level can be upgraded and subsequently light is created all through phosphorous crystallization, so this event is known as fluorescence.

It is an incredibly cleared cone shaped type of development. Within countenances of the CRT among the neck as well as the showcase are covered through the aqua-dag. This material is conductive and functions like a high-voltage electrode. The outer layer of the covering is associated electrically toward the speeding up anode to assist the electron with being the middle.

Working of Cathode Ray Oscilloscope

The CRO working principle relies upon the electron ray movement as a result of the electrostatic force. When an electron ray hits a phosphor face, then, at that point, it makes a splendid spot on it. A Cathode ray Oscilloscope applies the electrostatic energy on the electron beam from two vertical ways. The spot on the phosphor screen goes because of the impact of these two electrostatic forces which are opposite together. It moves to make the important waveform of the input signal.

The following circuit diagram shows the fundamental circuit of a cathode ray oscilloscope.

Working-of-CRO

• Vertical Deflection System : The primary capability of this amplifier is to amplify the weak signal so the amplified signal can create the ideal signal. To analyze the input signals are entered to the vertical deflection plates through the info attenuate and the quantity of amplifier stages.
• Horizontal Deflection System : The vertical and even framework comprises of flat intensifiers to enhance the frail info signals, however it is not quite the same as the upward avoidance framework. The flat diversion plates are entered by a range voltage that gives a period base. The saw-tooth wave generator is triggered by the synchronizing amplifier, as shown in the circuit diagram, while the sweep selector moves into the internal position. So the trigger saw tooth generator gives the contribution to the even enhancer by following the system. Here we will examine the four kinds of sweeps.
• Recurrent Sweep : As the name, itself says that the saw-tooth is individual that is another scope is begun indecently toward the finish of the previous sweep.
• Triggered Sweep : In some cases the waveform ought to be seen that it may not be anticipated hence, the ideal that the compass circuit stays out of commission and the scope ought to be started by the waveform under the assessment. In these cases, we will utilize the triggered sweep.
• Driven Clear : As a rule, the drive sweep is utilized when the sweep is free-running yet it is triggered by the signal under the test.
• Non-Saw Tooth Sweep : The purpose of this sweep is to determine the difference between the two voltages. Non-Saw Tooth Sweep By utilizing the non-saw tooth clear we can analyze the frequency of the input voltages.
• Synchronization : The synchronization is finished to create a fixed example. The synchronization is between the sweep and the signal should measure. There are a few wellsprings of synchronization that can be chosen by the synchronization selector. Which are discussed below.
• Internal : In this, the signal is estimated by the upward enhancer and the trigger is avoided by the signal.
• External : In the outer trigger, the outside trigger ought to be available.
• Line : The line trigger is delivered by the power supply.
• Intensity Modulation : This modulation is delivered by embedding the signal between the ground and cathode. This modulation causes by lighting up the display.
• Positioning Control : By applying the little autonomous inner direct voltage source to the recognizing plates through the voltmeter the position can be controlled and furthermore we have some control over the place of the sign.
• Intensity Control : The intensity has a distinction by changing the network potential as for the cathode.

Controls of Cathode Ray Oscilloscope

The fundamental controls of CRO primarily incorporate position, brightness, focus, astigmatism, blanking and calibration.

• Position : In the oscilloscope, the position control handle is mostly utilized for position control of the serious spot from the passed on side to the right side. By directing the handle, one can essentially control the spot from passed on side to the right side.
• Calibration Circuit : A calibration circuit for an oscilloscope requires an oscillator. Notwithstanding, the oscillator which is utilized ought to create a square waveform for preset voltage.
• Focus : By controlling the applied voltage in the direction of the CRO’s center anode, focus can be controlled. The center and different anodes in the district of it can shape the electrostatic focal point. As a result, the voltage across the center anode can be adjusted to change the main length of the lens.
• Blanking Circuit : The time base generator present in the oscilloscope created the blanking voltage.
• Brightness : The ray’s brightness mainly relies upon the power of the electron. The electron intensity of the electron ray is controlled by the control grids. As a result, the electron ray brightness can be adjusted to control the grid voltage.

Electrical Quantities Measurements using Cathode Ray Oscilloscope

Electrical quantities measurements by using CRO should be possible. They are

Measurement of Amplitude

Measurement of time period, measurement of frequency.

The display like CRO is used to show the voltage signal like a period capability on its presentation. This signal’s amplitude is constant; nonetheless, we can switch the quantity of allotments that cover around the voltage signal inside vertical way by evolving volt/division button on top of the CRO board. Thus, we will secure the signal amplitude, which is there on the CRO screen with the assistance of the below formula.

• ‘A’ is the Amplitude
• ‘j’ is the volt/division value
• ‘nv’ is the no. of partitions that vertically cover the signal.

CRO shows the voltage signal as an element of time on its screen. The Time period of that periodic voltage signal is consistent, however we can fluctuate the quantity of divisions that cover one complete pattern of the voltage signal in the flat heading by changing the time/division handle on the CRO panel.

In this way, we will get the Time period of the signal, which is available on the screen of CRO by using the accompanying formula.

• ‘T’ is the Time period
• ‘j’ is the time/division value
• ‘nv’ is the number of partitions that cover whole cycle of the periodic signal.

The horizontal scale on the CRO screen makes it simple to measure frequency and tile. To ensure exactness while estimating a recurrence, then, at that point, it helps to upgrade the region of the sign on your CRO show so we can all the more basically convert the waveform.

At first, the time can be counted using the horizontal scale on the CRO and the number of flat partitions from one end of the signal to the other wherever it crosses the flat line. From that point forward, we can foster the quantity of level allotments through the time or division to find the time span of the sign. Numerically the estimation of the recurrence can be connoted as frequency = 1/period.

Applications of Cathode Ray Oscilloscope

The applications of CRO are as follows:

• Waveform Analysis: The primary application of CROs is in the visualization and analysis of wave shapes. Researchers and architects can examine the duration, pattern, amount, and structure of electrical signals in the temporal space. This skill is essential for determining how symptoms behave and for identifying problems with electronic circuits. Used for Ensuring signal honesty by identifying wave form distortions, noise, and anomalies.
• Time Domain Analysis: The time area involves focusing on the long-term behavior of the signals. CROs provide a graphical representation that aids experts in understanding how signals fluctuate and interact with one another. Used for identifying signal anomalies and transient phenomena for the purpose of troubleshooting electronic circuits.
• Pulse and Transition Time Measurement: CROs are utilized to gauge beat widths and change times in computerized circuits. For evaluating digital system performance and timing characteristics, this capability is essential. Used for evaluating the response time of digital devices and verifying the integrity of digital signals.
• Voltage Measurement: CROs give a way to exact estimation of voltage levels in a sign. This capacity is central for describing and approving electronic frameworks. Used for measuring voltages, amplitudes, and DC offsets from peak to peak in a variety of electrical signals.
• Oscillator Testing: CROs assume a critical part in testing and examining the exhibition of oscillators , which create occasional wave forms. This incorporates evaluating the recurrence steadiness and waveform qualities of oscillators. Used for Checking the appropriate working of oscillators in electronic frameworks.
• Filter Testing: Engineers use CROs to assess the exhibition of electronic channels by noticing their impacts on wave forms. This includes evaluating filters’ frequency response and attenuation properties. Used for Checking the usefulness and viability of channels in signal handling applications.
• Frequency Measurement: CROs take into consideration precise estimation of the recurrence of dreary waveform. The time base settings on the oscilloscope assist with deciding the time span of the sign, empowering exact recurrence estimations. Used for Confirming the recurrence of swaying signals in electronic circuits for legitimate working.
• Transient Analysis: CROs are pivotal for catching and breaking down transient peculiarities in electronic circuits. Homeless people are unexpected and fleeting changes in voltage that can affect the security and dependability of a framework. Used for Contemplating and investigating abrupt changes or aggravations in electronic circuits, for example, voltage spikes or errors.
• Measurement of Phase: CROs work with the estimation and perception of stage contrasts between different signs. Here the timing connection between signals is critical. It is used for Guaranteeing synchronization and arrangement of signs in correspondence frameworks or control circuits.
• Sound and Video Applications: CROs track down applications in the sound and video industry for examining signals connected with sound and picture handling. This includes checking the quality of the video signal or the frequency response of the audio. It is used for Guaranteeing the quality and constancy of sound and video signals in communicating, diversion, and media applications.

Advantages of Cathode Ray Oscilloscope

• Real-time Visualization: CRO gives continuous perception of electrical signals, permitting clients to notice wave structures and signal attributes as they happen.
• Dynamic Signal Observation: CROs empower the perception of dynamic signal changes, making them important for concentrating on quickly evolving signals, for example, pulse or regulated wave structures.
• High Accuracy: CROs are reliable instruments for precise signal analysis because they measure waveform parameters like amplitude, frequency, and phase with high accuracy.
• Versatility : Due to their versatility in waveform analysis, CROs can be used in a variety of fields, including electronics, telecommunications, medicine, and physics.
• Tool for Education: CROs are useful tools for teaching electronics because they give students a chance to see and understand electrical signals in action.
• Time Domain Analysis: CROs are fundamental for time space examination, permitting clients to concentrate on the way of behaving of signals after some time and break down transient peculiarities in electronic circuits.
• Easy to use : With current digital CROs, UIs are natural, and highlights like programmed estimations and on-screen menus upgrade client experience, making them open for a great many clients.
• Quick Troubleshooting: CROs work with fast recognizable proof and investigating of electronic circuit issues by giving a visual of signals, empowering specialists to pinpoint irregularities.

Disadvantages of Cathode Ray Oscilloscope

• Susceptibility to Electromagnetic Interference: CROs can be delicate to electromagnetic obstruction, which might influence signal exactness. Protecting and cautious arrangement are important to limit obstruction.
• Limited Bandwidth : Some CRO models might have restricted transmission capacity, limiting their capacity to precisely address high-recurrence signals. High-recurrence applications might require particular oscilloscopes.
• Cost: Excellent CROs can be generally costly, particularly those with cutting edge highlights. This cost element might be a thought for spending plan compelled clients or little research facilities.
• Limited Storage Capacity : Simple CROs might have restricted capacity limit with regards to waveform information. While computerized CROs offer better information stockpiling, the capacity limit is limited and might be a constraint in specific applications.
• Mass and Weight: The weight and bulk of traditional analog CROs can make them difficult to transport. While present day computerized oscilloscopes are more minimal, size and weight can in any case be a worry in specific applications.
• Risk of Electric Shock: Cathode ray tubes have high voltages, which can cause electric shock if proper safety precautions are not taken during maintenance or repairs.
• Complexity for Novice Users: For inexperienced users, some CROs’ advanced features may be overcome. Preparing and experience with the instrument are fundamental for ideal use, particularly in complex applications.

In conclusion, the Cathode Ray Oscilloscope (CRO) continues to be a versatile and indispensable tool in the field of electronic testing and inspection. Due to its ability to provide continuous electrical sign perceptions, high waveform measurement accuracy, and versatility, this device is indispensable for professionals, researchers, and educators. The CRO’s significance in modern devices is demonstrated by its involvement in the study of dynamic sign characteristics, time-area conduct, and electronic circuits. Even though there are challenges such as limited data transfer capacity, inability to overcome impedance, and maintenance requirements, the advantages that CROs offer in terms of quick diagnosis, precise measurements, and educational value exceed these challenges.

FAQs on Cathode Ray Oscilloscope

Can cathode ray oscilloscope measure ac and dc signals.

A Cathode Ray Oscilloscope can used to measure both direct current (DC) and alternating current (AC) signals. It is a versatile instrument that can deal with many different kinds of signals.

Can audio and music applications utilize a CRO?

Indeed, CROs track down applications in sound and music ventures for examining signs like sound waves and electrical signs in sound gear. Audio signal distortion, amplitude, and frequency response can all be evaluated with their assistance.

What is the contrast among analog and digital CROs?

Simple CROs utilize simple innovation with cathode beam tubes, while computerized CROs utilize advanced handling for signal examination. Computerized CROs offer extra highlights like capacity, progressed setting off, and signal handling abilities.

What elements should to be thought about while picking a CRO for specific applications?

Variables to consider incorporate data transfer capacity prerequisites, signal sorts, estimation exactness, versatility, and spending plan requirements. Clients ought to match the particulars of the CRO to the particular necessities of their applications.

Are there safety considerations while utilizing a CRO?

Indeed, security is significant while working with a CRO. In order to avoid electric shock, users should be aware of high voltages, follow proper grounding procedures, and take precautions. Personnel with the proper training should carry out maintenance and repairs.

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Cathode Ray Oscilloscope  ( CRO ) Definition: The  cathode ray oscilloscope  ( CRO ) is a type of electrical instrument which is used for showing the measurement and analysis of waveforms and others electronic and electrical phenomenon. It is a very fast X-Y plotter shows the input signal versus another signal or versus time.

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Syllabus Edition

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Cathode-Ray Oscilloscope ( CIE A Level Physics )

Revision note.

Cathode-Ray Oscilloscope

• A Cathode-Ray Oscilloscope is a laboratory instrument used to display, measure and analyse waveforms of electrical circuits
• An A.C. current on an oscilloscope is represented as a transverse wave. Therefore you can determine its frequency and amplitude
• The x-axis is the time and the y-axis is the voltage ( or y-gain)

Diagram of Cathode-Ray Oscilloscope display showing wavelength and time-base setting

• This is how many seconds each division represents measured commonly in s div -1 or s cm -1
• Use as many wavelengths shown on the screen as possible to reduce uncertainties
• Dividing the total time by the number of wavelengths will give the time period T (Time taken for one complete oscillation)
• The frequency is then determined through 1/T

Worked example

The time-base setting varies with units for seconds (commonly ms) and the unit length (commonly mm). Unit conversions are very important for the calculate of the time period and frequency

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The Cathode-Ray Oscilloscope

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• G. H. Olsen B.Sc., C.Eng., A.M.I.E.R.E., A. Inst. P. 2  

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The modern cathode-ray oscilloscope is designed as a measuring instrument, and is the most useful of all electronic test devices. So great is its versatility that workers in every branch of scientific activity now find the instrument to be almost indispensable. If limited to the purchase of a single item of electronic measuring equipment, the majority of experienced workers would select an oscilloscope.

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Attew, J. E. ‘Decade multivibrator design’. Wireless World , 1952, 58 , No. 2 (March).

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W.T.C. Wireless World , Oct. 1952, p. 432. (The author suspects that W.T.C. = W. T. Cocking, a regular contributor to this journal.)

Briggs, G. A., Sound Reproduction. Wharfedale Wireless Works, 3rd. Edn, 1953.

Gooder, A. W. ‘A simple and inexpensive method of tracing cathode-ray tube waveforms’. J. Sci. Instrum. 1964, 41 p. 392.

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Hercock, R. J. The Photographic Recording of Cathode-ray Tube Traces. Ilford Technical Monographs, 1947.

Suggestions for Further Reading

The Cathode-ray Oscilloscope by J. Czech, Philips Technical Library, 1957. The Oscilloscope at Work by A. Haas and R. W. Hallows, Iliffe and Sons Ltd. 1954.

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Olsen, G.H. (1968). The Cathode-Ray Oscilloscope. In: Electronics. Springer, Boston, MA. https://doi.org/10.1007/978-1-4899-6535-6_11

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Virtual Lab

Evaluating the ac/dc signal parameters using function generator and cro, function generator:.

Function Generator is an instrument that can generate common waveforms like triangle, sine, cosine, square, sawtooth, etc., It also provides options for changing the characteristics of the waveforms such as amplitude and frequency. The wave generated is available at the output jack. It can be visualised by connecting it to the CRO.

citation : image of function generator taken from tradeindia.

Cathode Ray Oscilloscope - CRO:

CRO which stands for Cathode Ray Oscilloscope is an electronic instrument used to visualize waveforms. In the early days, it is also called an oscillograph. The instrument has four sections namely display, x-axis controls, y-axis controls and triggers. CRO is mainly used to analyse the properties of the waveforms

citation : image of cro taken from amazon.in.

Sine wave is a periodic wave defined by the function. y = sin(x)

• RMS value of Sine wave = Peak Value / √2
• The Average value of Sine wave = 2 × Peak Value / π

Cosine wave:

Cosine wave is also a periodic wave defined by a function. y=cos(x)

• RMS value of Cosine wave = Peak Value / √2
• The Average value of Cosine wave = 2 × Peak Value / π

Square wave:

Square wave also called pulse wave is a periodic waveform having an equal positive and negative pulse width. generally called as 50% duty cycle.

• RMS value of Square wave = Peak Value
• The Average value of Square wave = Peak Value

Sawtooth wave:

The sawtooth wave is in a way of the non-sinusoidal waveform. The shape of the wave resembles the teeth of a saw so it is named as sawtooth wave. The sawtooth waveform ramps upward and then drops sharply. But, in a "reverse sawtooth wave", the wave goes downward and then sharply rises. It can also be viewed as the extreme case of an asymmetric triangle wave. The piecewise linear function based on the floor function of time t is an instance of a sawtooth wave with period 1. A more general form, in the range from −1 to 1, and having period a, is This sawtooth function has the same phase as the sine function.

• RMS value of Sawtooth wave = Peak Value / √3
• The Average value of Sawtooth wave = Peak Value / 2

Triangular wave:

Triangular waves have a triangular shape which is a periodic and non-sinusoidal waveform. Time and again people get confused between the triangle and sawtooth waves. The distinguishing feature of a triangular wave is that it has equal rise and fall times. To generate a triangular waveform we need an input wave, we are using square waves for input. Similar to the triangular waves, square waves have equal rise and fall times so they are more suitable to be converted to a triangular waveform. The triangle waveform increases gradually along a straight line to its maximum value, and then gradually decreases along a straight line to its lowest value, and then starts increasing again. By repeatedly charging and discharging a capacitor from a constant current source, the triangular wave is generated. Therefore it produces a linearly ascending and descending voltage ramp.

• RMS value of Triangular wave = Peak Value / √3
• The Average value of Triangular wave = Peak Value /√3

CRO – Cathode Ray Oscilloscope – Ultimate Guide

A CRO (Cathode Ray Oscilloscope) is an electronic instrument used for studying various electrical & electronic parameters and behaviors. CRO is basically an XY (2 dimensional) plotter which can plot an input signal vs another signal or an input signal vs time. A cathode ray oscilloscope is used to study waveforms, transients, time based or frequency based analysis.

Introduction to CRO – Cathode Ray Oscilloscope

The cathode ray oscilloscope is an extremely useful and versatile laboratory instrument used for studying wave shapes of alternating currents and voltages as well as for meas­urement of voltage, current, power and frequency, in fact, almost any quantity that involves amplitude and waveform. It allows the user to see the amplitude of electrical signals as a function of time on the screen. It is widely used for trouble shooting radio and TV receivers as well as laboratory work involving research and” design. It can also be employed for studying the wave shape of a signal with respect to amplitude distortion and deviation from the normal. In true sense the cathode ray oscilloscope has been one of the most important tools in the design and development of modern electronic circuits.

Buyers Guide – We have developed an excellent buyers guide for people who are looking to buy a CRO. So here is our first guide to  Buy an Analog Oscilloscope – which explains which all features to look for, compares the top selling products and much more.

Block Diagram of a CRO

The instrument employs a cathode ray tube (CRT), which is the heart of the oscilloscope. It generates the electron beam, accel­erates the beam to a high velocity, deflects the beam to create the image, and contains a phosphor screen where the electron beam eventually becomes visible. For accomplishing these tasks various electrical           signals and voltages are required, which are provided by the power supply circuit of the oscilloscope. Low voltage supply is required for the heater of the electron gun for gen­eration of electron beam and high voltage, of the order of few thousand volts, is required for cathode ray tube to accelerate the beam. Normal voltage supply, say a few hundred volts, is required for other control circuits of the oscilloscope.

Horizontal and vertical deflection plates are fitted between electron gun and screen to deflect the beam according to input signal. Electron beam strikes the screen and creates a visible spot. This spot is deflected on the screen in horizontal direction (X-axis) with constant time dependent rate. This is accomplished by a time base circuit provided in the oscilloscope. The signal to be viewed is supplied to the vertical deflection plates through the vertical amplifier, which raises the potential of the input signal to a level that will provide usable deflection of the electron beam. Now electron beam deflects in two directions, horizontal on X-axis and vertical on Y-axis. A triggering circuit is provided for synchronizing two types of deflections so that horizontal deflection starts at the same point of the input vertical signal each time it sweeps. A basic block diagram of a general purpose oscilloscope is shown in figure. Cathode ray tube and its various components will be discussed in the following Arts.

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How induction cooktops work, basic controls of a cro, crt-cathode ray tube, 36 comments.

NICE & THANKS

it is very good and is better than others.

IT VERY USEFUL

:-OIt is so large for practical theory.B-)But it is good for knowledge study. :-)THANK YOU;-)

most thanks

i think…delay line is responsible synchronising…

it is very useful to information to me

Thanque so much ..cro information is useful*

delay line basically used for delaying the input signal nearly around 80 to 200ns. you have not mentioned in it

nothing given regarding function of delay line

Thank you very much it was usefull for me in understanding cro better…..

information is very usefulto us thank you…………

a very useful study on CRO, thanks for this info

me too need the complete working of cro…

dear sir i need complete using procedure on cro . analog and digital circuits signal testing procedure via cro please help to me

It is very useful information to me.

thanx was very useful information

Hi Ankit go through the wiki site full of details. http://en.wikipedia.org/wiki/Oscilloscope

i need complete information in cro & function of cro.

love the pic of stevy wonder ……(wtf)

i need CRO FUNCTION… and how i can to calibrate to one step…

Each component of the oscilloscope has very important function. If one of them fails, it will give faulty readings.

u r material is so nice i want more information about cro and about picture tube and some pics of that so plz u send me quick

you could have explained the function of each block

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