What is "sense amplifier"

n. An electronic circuit used to refresh the value of a bit stored in a DRAM integrated circuit

In modern computer memory, a sense amplifier is one of the elements which make up the circuitry on a semiconductor memory chip ( integrated circuit); the term itself dates back to the era of magnetic core memory. A sense amplifier is part of the read circuitry that is used when data is read from the memory; its role is to sense the low power signals from a bitline that represents a data bit (1 or 0) stored in a memory cell, and amplify the small voltage swing to recognizable logic levels so the data can be interpreted properly by logic outside the memory.

Modern sense-amplifier circuits consist of two to six (usually four) transistors, while early sense amplifiers for core memory sometimes contained as many as 13 transistors. There is one sense amplifier for each column of memory cells, so there are usually hundreds or thousands of identical sense amplifiers on a modern memory chip. As such, sense amplifiers are one of the only analog circuits in a computer's memory subsystem.