Electron beam focused to a fine spot, Electrical Engineering

Assignment Help:

Q. How is the electron beam focused to a fine spot on the face of the CRT?

Sol. The functional diagram of an electrostatic focusing arrangement is shown below. The pre-accelerating anode, which is a metal cylinder containing many baffles, collimates the electron beam which enters it through a small opening on the left hand side. The pre-accelerating anode is connected to a high positive potential.

The focusing anode and the accelerating anodes are co-axial with the pre-accelerating anode. The pre-accelerating and accelerating anodes are connected to the same potential while the focusing anode is connected to a lower potential.

On account of difference of potential between focusing anode and the two focusing anode. The equipotential surfaces thus form a "double concave".

The electron beams entering the field at angles other than the normal to the equipotential surfaces, will be deflected towards the normal and the beam is thus focused towards the centre of the tube axis. By changing the voltage of the focusing anode, the refractive index of the electron lens is changed and therefore the focal point of the beam can be changed. The change in voltage is brought about by chanting the setting of potentiometer. This control is brought to the front panel of CRO and is marked focus.

 

 


Related Discussions:- Electron beam focused to a fine spot

Computes similarity between two histograms, Write an m-file "distan.m"  whi...

Write an m-file "distan.m"  which does all the following operations: (i) computes 10 dimensional histogram of an input image             h1=sum(hist(imn,10)'); (ii) computes

What do you mean by digital systems, Q. What do you mean by digital systems...

Q. What do you mean by digital systems? Electronics information is generally placed into two categories as digital and analog. The Digital information is represented in discret

Simulation in Proteus, Hi, I need help simulating my project in Proteus, ...

Hi, I need help simulating my project in Proteus, problem is, I have never used it before. This is what I have so far. However, feel free to suggest ideas that will make the circ

Weighted resistor and the r-2 r ladder d/a converters, Q. What is the basic...

Q. What is the basic difference between the weighted resistor and the R-2 R ladder D/A converters?

Finite state machine, the tutorial assignment is part of my thesis work and...

the tutorial assignment is part of my thesis work and i need help in it please

Thevenins theorem, advantages and disadvantages of thevenins theorem

advantages and disadvantages of thevenins theorem

Determine the current through each resistor, For the circuit of Fig 1a: ...

For the circuit of Fig 1a: (i) Using Ohm's Law , determine the equivalent resistance across the battery (ii)  determine the current through each resistor (iii) the arrang

Draw a state diagram of 3-bit ripple counter, The block diagram for a 3-bit...

The block diagram for a 3-bit ripple counter is shown in Figure (a). Obtain a state table for the number of pulses N = 0 to 8, and draw a state diagram to explain its operation.

Plug and socket condition -safe conduct, Plug and Socket Condition : In th...

Plug and Socket Condition : In the same way that your knowledge of flexes and fuses is wasted if you don't care to ensure that flexes and cables are routed safely and sensibly, so

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd