Matt writes about creating one bit of RAM from individual transistors.
RAM is short for Random Access Memory. It stores data while the computer is powered and running but loses that data when the computer is reset or powered off. RAM is a crucial component of any computer. It allows the computer to store data temporarily and then access later on in program execution.
Today we are going to use NPN transistors to construct one bit of RAM. I use three breadboards but you can squash everything together on half or less than half a breadboard, you can even use the prototyping board to reduce the size even further.
Here a schematic of how the RAM will work. There is a Data connection that goes into one AND gate and goes through an inverter into another and gate simultaneously. They enable the connection to go into both gates as well. The output of both AND gates go into two different NOR gates. The other input for both the NOR gate comes from the output of the opposite NOR gate. This sounds complicated but it’s not, make sure you have looked at and understand the truth tables of the logic gates. This is called a D latch and it’s near perfect for building RAM. Q is the main output.