||The early personal computers were single board systems that used one of the 8-bit microprocessors.
Intel invented the microprocessor with their 4004, 8008, 8080 and 8085. Hal Communications and the Mits Altair used an 8080. The TektronixBoardBucket used an 8085.
Motorola quickly followed Intel with a microprocessor of their own, the 6800. The Wince Control Module and the MitsSixEighty used a 6800.
The 6800 was cloned as the very similar 6502. The AppleTwo used a 6502.
Intel added memory and i/o to the microprocessor to make the first single chip microcomputers, the 8048. Wayne Downer built one of these up into a Single Chip Morse Teacher.