Q1 Computer
The Q1 Computer is a project of mine to build a fully functional 8-bit
computer with 16-bit address bus completely out of transistors. Of course,
there is some support circuitry required, most notably, I'm using an SRAM
for the main memory. However, other than the memory, power supply, and LEDs,
all semiconductors are NPN transistors (PN2222A).
Here's a high-level block diagram: