[wiml]

Each type of memory has a somewhat different design, but generally, the address lines will control a pair of demultiplexers, one which activates a single row in a rectangular grid of memory cells, and one which reads a single column. (Old DRAM chips had separate RAS and CAS — row address select and column address select — phases.) Each memory cell in that row puts its value onto its column line, and the column portion of the address determines which column line is routed to the output pin and fed back to the data bus. Multiply everything by 16 for a 16-bit memory bus.

The memory cell itself might be a handful of transistors forming a bistable flipflop (for SRAM), or it might be a capacitor and transistor (for DRAM), or a floating gate and transistor (for EPROM), or just a wire and transistor (for mask-ROM).

[kaba0]

For (much) more detail I can recommend Drepper’s “What every developer should know about memory” paper. Don’t be afraid by its publication date, it is still very very relevant.