Memory cell (computing)

The memory cell is the fundamental building block of computer memory. The memory cell is an electronic circuit that stores one bit of binary information and it must be set to store a logic 1 (high voltage level) and reset to store a logic 0 (low voltage level). Its value is maintained/stored until it is changed by the set/reset process. The value in the memory cell can be accessed by reading it.

Over the history of computing, different memory cell architectures have been used, including core memory and bubble memory. Today^{[as of?]}, the most common memory cell architecture is MOS memory, which consists of metal–oxide–semiconductor (MOS) memory cells. Modern random-access memory (RAM) uses MOS field-effect transistors (MOSFETs) as flip-flops, along with MOS capacitors for certain types of RAM.

The SRAM (static RAM) memory cell is a type of flip-flop circuit, typically implemented using MOSFETs. These require very low power to maintain the stored value when not being accessed. A second type, DRAM (dynamic RAM), is based on MOS capacitors. Charging and discharging a capacitor can store either a '1' or a '0' in the cell. However, since the charge in the capacitor slowly dissipates, it must be refreshed periodically. Due to this refresh process, DRAM consumes more power, but it can achieve higher storage densities.

Most non-volatile memory (NVM), on the other hand, is based on floating-gate memory cell architectures. Non-volatile memory technologies such as EPROM, EEPROM, and flash memory utilize floating-gate memory cells, which rely on floating-gate MOSFET transistors.