If you consider the word “screen” to be synonymous with the word “monitor,” then you know that in order for it to work, there must also be a difference between two opposite electric fields charged up or created in opposite directions. The screen or monitor is where the video displays are located and there are input/output ports designed for individual peripherals. It works because when an electron travels around in circles, it produces tubes of electrons at certain distances which form electronic images on the screen. With the tubes of electrons charged up in opposite directions, they can detect their differences when they bounce off one another when there is something displayed on the screen.