What causes the electron beam to move across the screen in a regular pattern in a raster - scan CRT?

The electron beam to move across the screen in a regular pattern in a raster - scan CRT : 

The deflection yoke which is connected to the sweep generator creates a fluctuating electric or magnetic potential. The change in potential causes the electron beam to be deflected.

If You want to learn about the technology, computer science & engineering, web programming, freelancing, earning please click here :CSE SOLVE