When do we use cathode ray tube?
Cathode Ray Tube is used in terms of light (
Total Internal Reflection); every time the ray of light within totally internally reflects and therefore the light ray remains within the tube. An example of its use is in the transfer of TV signals.
For Electricity, its the
Cathode Ray Oscilloscope that you need to know. CRO is just a vaccuum tube containing a Cathode, which emmits electrons due to
thermionic emission (after its heated). The electron beam then gains enough of kinetic energy to leave the cathode and then it travels through the vacuum (REMEMBER, electrons must be in a vacuum in order to move <in air, the air molecules would stop the electrons from moving>). Then they get attracted to the anode (positive). However, before that, they have to pass a
grid(negative), which would repel some of the electrons, by changing the voltage on the base it is used as a brightness control. Then, a ray of electrons would pass through a hole in the anode. On their way after passing the hole, the electrons ray will meet
Y-plates and
X-Plates. Y-plates would move the spot on the Fluoresecent screen afterwards up and down and the X-plates would move the coloured spot produced left and right on the fluorescent screen. At the end, the Fluorescent screen would
glow, when hit by the electrons ray.
For the question you asked, its not CRO, as there is no need to make a screen glow. Its just about detection. So, you would just use a simple source, absorber, detector arrangement.
I hope this brief explanation helped.
