im Stucked here with this diagram...
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What is a Cathode Ray Oscilloscope?
A Cathode Ray Oscilloscope (CRO) is an instrument generally used in a laboratory to display, measure and analyze various waveforms of electrical circuits. A cathode ray oscilloscope is a very fast X-Y plotter that can display an input signal versus time or another signal.
Cathode ray oscilloscopes use luminous spots which are produced by striking the beam of electrons and this luminous spot moves in response variation in the input quantity. At this moment one question must be arise in our mind that why we are using only an electron beam? The reason behind this is low effects of beam of electrons that can be used for following the changes in the instantaneous values of rapidly changing input quantity. The general forms of cathode ray oscilloscope operate on voltages..
So the input quantity that we have talked above is voltage. Nowadays, with the help of transducers it is possible to convert various physical quantities like current, pressure, acceleration etc to voltage thus it enable us to have a visual representations of these various quantities on cathode ray oscilloscope. Now let us look at the constructional details of the cathode ray oscilloscope.
Construction of Cathode Ray Oscilloscope
The main part of cathode ray oscilloscope is cathode ray tube which is also known as the heart of cathode ray oscilloscope.
internal structure of crt
Let us discuss the construction of cathode ray tube in order to understand the construction of cathode ray oscilloscope. Basically the cathode ray tube consists of five main parts:
Electron gun
Deflection plate system
Fluorescent screen
Glass envelope
Base
You will need all 5 of these components to build your own DIY oscilloscope. We’ll now discuss these 5 components in detail:
Electron Gun:
It is the source of accelerated, energized and focused beam of electrons. It consists of six parts namely heater, a cathode, a grid, a pre-accelerating anode, a focusing anode and an accelerating anode. In order to obtain the high emission of electrons the layer of barium oxide (which is deposited on the end of cathode) is indirectly heated at moderate temperature. The electrons after this passes through a small hole called control grid which is made up of nickel. As the name suggests the control grid with its negative bias, controls the number of electrons or indirectly we can say the intensity of emitted electrons from cathode. After passing through the control grid these electrons are accelerated with the help of pre-accelerating and accelerating anodes. The pre-accelerating and accelerating anodes are connected to a common positive potential of 1500 volts.
Now after this the function of the focusing anode is to focus the beam of the electrons so produced. The focusing anode is connected to adjustable voltage 500 volts. Now there are two methods of focusing the electron beam and are written below:
Electrostatic focusing.
Electroma