A transistor based T flip flop circuit. It uses 15 transistors, making 6 NAND gates. The design is based on an edge-triggered D flip-flop with one output fed into Data, and the user input acting as clock.
The design is a direct transfer of the logic-gate design into transistors. Each gate is fully built, which makes this a bit innefficent on part usage, but it's very simple design-wise. ( there's also lights for output, and a button for input ). The main challenge was figuring how to best use the limited resistor selection I had access to, without breaking the circit with a ton of random variance.
For the PCB, I just tried to fit the schematic inside the logic diagram, to some degree of sucess. The design on the back is the result of asking as many people as possible what they thought should go there. I have ( almost ) no complaints.
I've yet to assemble, but I will update this page once I do.