Dynamic random-access memory (DRAM) is a type of random-access memory that stores each bit of data in a separate capacitor within an integrated circuit. The capacitor can be either charged or discharged .these two states are taken to represent the two values of a bit, conventionally called 0 and 1. Since capacitors leak charge, the information eventually fades unless the capacitor charge is refreshed periodically.The advantage of DRAM is its structural simplicity. only one transistor and a capacitor are required per bit, compared to six transistors in SRAM. This allows DRAM to reach very high densities