Diagram below show the typical flyback. This flyback mostly found in a direct view color television or computer monitor. The right side show us the high voltage section. This section consist of HV to CRT, focus, and screen divider network. On monochrome an black-and-white TV, the flyback transformer do not have screen divider and focus.

flyback circuit schematic

The flyback have a ferrite core that constructed with precision gap that mostly made from pieces of tape or plastic spacer. For focus and screen divider we use a potentiometer and resistor with value 10s to 100s M ohm. D1 to D3 are used to rectify the high voltage that will read open on typical DMM or VOM