Cathode Ray Tube Voltages
Question:
In doing the experiment on finding effect of electric field alone
on electron beam, there are two voltages supplied. One is to the
cathode and anode, while the other is to the electric plates
creating the electric field. Should the two voltages have a
common earth? If yes, why is it necessary to have the zero
voltage together?
Answer:
The deflection electrode voltage should be at the common earth
(cathode) potential when neutral. To deflect the beam, one plate
should go positive relative to the common and the other negative
relative to the common to have a symmetrical effect.