Electron beam focused to a fine spot, Electrical Engineering

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.



Posted Date: 7/12/2012 6:17:05 AM | Location : United States

Related Discussions:- Electron beam focused to a fine spot, Assignment Help, Ask Question on Electron beam focused to a fine spot, Get Answer, Expert's Help, Electron beam focused to a fine spot Discussions

Write discussion on Electron beam focused to a fine spot
Your posts are moderated
Related Questions
Architecture of 8085 Microprocessor The 8085  microprocessor  is an 8 bit  general purpose microprocessor. 8 bit  processor  means it can  read write  and process 8 bit  data

A data hold is to be constructed that reconstructs the sampled signal by the straight-line approximation shown in Figure. Note that this device is a polygonal data hold with a dela

Using the optimized 6-311G(d,p) geometry determined in question 1, perform the following equivalent core calculations for any two inequivalent carbons of butadiene: (a) Equivale

Torque-Speed Characteristics of 3-Phase Induction Motors Because the torque-slip characteristic is one of themost important aspects of the inductionmotor, we will now develop a

what are the grond clearance for 220KV overhead transmission lines?

hi can you help me to create a dc to 3 phase ac circuit which can exceed at any point: 50V and 20A and 400W maximum. The output should be variable from about 0 – 25V per phase, wi

Q. A low-pass filter circuit is shown in Figure. Using a PSpice program and PROBE, obtain the Bode magnitude plot for the transfer function ¯H(f) = ¯V out / ¯V in for the frequ

Consider the following IIR filter. The initial input data sequence is given by x n = [10 15 20 15 8 6 9 0 0 0] Construct a table that shows the corresponding signal values at

Q. What do you mean by Resistance? An ideal resistor is a circuit element with the property that the current through it is linearly proportional to the potential difference acr

1. The circuit below will be most efficiently analyzed by obtaining the Thevenin equivalent circuit for the circuit to the left of the points (a-b) on the schematic. The capacitor