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

Determine the sampling rate, Q. If an analog message that has a spectral ex...

Q. If an analog message that has a spectral extent of 15 kHz is sampled at three times the Nyquist rate, determine the sampling rate.

Metering techniques, Metering Techniques The techniques of metering co...

Metering Techniques The techniques of metering could be categorized depending upon the voltage at which consumers are fed as: 1. LT (Low Tension) Metering, and 2. HT (Hi

Give some applications of nichrome, Give some applications of nichrome. ...

Give some applications of nichrome. Nichrome is an alloy of iron, chromium, nickel and manganese. This is used for electric iron, for making heating elements and another hea

Develop an electric equivalent network, Q. For the mechanical spring-mass-f...

Q. For the mechanical spring-mass-friction system shown in Figure, the differential equation relating the force F(t) and the velocity u(t) is given by  where M is themass,D

Produce electrical power using solar cell - electrical power, 1. Suppose th...

1. Suppose the California government sets aside a square patch of land that is 10 kilometers on each side and plans to use this land to generate electrical power with wind turbines

Rftfrfr, #questionfrfrfrfr..

#questionfrfrfrfr..

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