Computer means calculator. Its only job is to process numbers. We use this ability by assigning meaning to numbers. They can stand for many things, a character from the alphabet, a color of a pixel, the magnitude of a voltage, etc.
In this video I want to explain how such a CPU works with the other components in the computer using the example of the Zilog Z80, using my old Z 1013 computer kit.

0:00 - Foreword
2:16 - Block diagram of a computer
5:31 - The wiring of the CPU
7:39 - CPU internal
10:07 - Program execution
10:43 - BIOS and OS
11:23 - The Z 1013
13:20 - The machine code
14:55 - Demo program
18:16 - Translation into machine code
19:54 - Step-by-step processing
25:09 - Screen output on the Z 1013
26:12 - sample program
27:27 - The interrupt
28:47 - The Stack
31:56 - Closing Remarks