THe RS-latch (Reset-Set latch) is a basic form of "memory." This one tends to be a bit mind blowing, despite how simple it is. Remember, it relies on the omitted ground and power pins to maintain power, so if the power is removed from the board, the data stored in the latch will be destroyed.

The general idea is, if "S" gets connected to the voltage (evaluates as true), a true will inevitably get caught between the two NAND operations, and it'll stay there even when "S" looses it's connection, as long as the omitted pins (to ground and voltage source) are connected and functional. The false will get caught in that nesting if "R" gets evaluated as true. Note that, as before, the wires are only touching the other wires if you see the big dot, thus it's the gates themselves that are "getting stuck."

Now, if you combine 8 of these with the multiplexers and demultiplexers, we can create 8bit "memory" that can be selected.

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