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

What is the basic working of decoders, Q. What is the basic working of Deco...

Q. What is the basic working of Decoders? An n-bit binary code is capable of encoding up to 2 n distinct elements of information. A decoder is a combinational network that decode

Reduction of sequential monte carlo in medium voltage, how can optimized th...

how can optimized the system through the matlab software?

Electrons, Ask question #Minimum 100 words accepted how does the charge pla...

Ask question #Minimum 100 words accepted how does the charge plate relate to the movement of electrons

Describe about absolute poverty, Q. Describe about Absolute Poverty? Po...

Q. Describe about Absolute Poverty? Poverty defined with respect to an absolute material standard of living. A person is absolutely poor if their income does not allow them to

Microprocessor, Write a program to count how many from your data set called...

Write a program to count how many from your data set called MYDATA, which is a set of signed single-byte numbers, has positive value and are odd numbers. Save the result in POSOD

Application of plc - stepper motor , Application of PLC a. A PLC  is us...

Application of PLC a. A PLC  is used to start  and stop  the motors  of a segmented conveyor beli. This  allows  only belt section carrying  a copper plate to move. b.In aut

Draw the power triangle for each load, Q. Two balanced, wye-connected, thre...

Q. Two balanced, wye-connected, three-phase loads are in parallel across a balanced, three - phase 60- Hz, 208-Vsupply. The first load takes 12 kWat 0.6 power factor lagging, and t

Digital electronics, an 8 bit successive approximation adc has a resolution...

an 8 bit successive approximation adc has a resolution of 20mv. what will be its ouput analogue input of 2.17v

Determine variation of large scale integration chips, Large scale integrati...

Large scale integration chips have between (A) Less than 10 components.         (B) 10 and 100 components. (C) 100 and 1000 components.       (D)  More than 1000 componen

Find the value of noncoherent source, If E b /N 0 = 20 in a coherent ASK s...

If E b /N 0 = 20 in a coherent ASK system, find the value of Eb/N0 that is needed in a noncoherent ASK system to yield the same value of Pe as the coherent system.

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