|If black is a high current from the television's radio receiver and white is a low current, why do you get a bright spot when you increase the flow of electrons at that instant. Isn't white a bright spot?
Yes, white is created by a strong flow of electrons. There are two separate circuits here. The current from the receiver section of the television isn't what is sent through the electron gun. Instead, that current controls the electron gun. When a large current arrives at the electron gun (actually the grid) from the receiver, the flow of electrons toward the screen is pinched off and a dark spot is created. When a small current arrives from the receiver, the electron beam remains intense and a bright spot is created.