CRT High Voltage: Why Does It Need It?

[doc.madani]

Why does a cathode ray tube (CRT) require a high voltage to operate?

 

[Dadface]

What part of the CRT circuitry are you referrring to?

 

[doc.madani]

the input voltage/energy required, so that the cathode ray gun has enough energy to fire the electron/cathode ray.

 

[Dadface]

Think of the energy conversions that occur
PE(eV) to KE(as electrons fly through the tube) to light energy as the electrons strike the screen.
The accelerating voltage(V) must be big enough such that photons in the required visible region of the spectrum are released.