I'm currently learning about the operation of 6 transistor static random access memory cells and I've hit a wall in understanding exactly how the read/write operations work. More specifically I don't get the gate transistors that control whether the cell is connect to the bit lines or not. Firstly, since the "information gates" are just single FETs, there is the problem of there being no voltage drop across them, so ultimately they don't act as gates at all. A simple solution would be to somehow connect the bit lines to ground (which seems like a terribly inefficient way to fix this problem since that would create a constant current). How do people solve this? How do you read and write data onto SRAM cells efficiently and reliably?
For a visual aid I've created an SRAM cell in a simulator to show the problem. The bit lines are the wires on the very right and left. As you can see, one of the wires has voltage while the other does not. Ideally they would both have no voltage until I activated the word line (the wire on top) which would open up the transistor "gates". Essentially the gate transistors are useless as for the moment. How do I get them to work?
SRAM cell in circuit simulator: