sentences:  The electric charge on the capacitors slowly leaks off, so without intervention the data on the chip would soon be lost.To prevent this, DRAM requires an external "memory refresh" circuit which periodically rewrites the data in the capacitors, restoring them to their original charge.This refresh process is the defining characteristic of dynamic random-access memory, in contrast to static random-access memory (SRAM) which does not require data to be refreshed.