In a dynamic RAM cell, binary data is stored simply as charge in a capacitor, where the or absence of stored charge determines the value of the stored bit. Note that the stored as charge in a capacitor cannot be retained indefinitely, because the eventually remove or modify the stored charge. Thus, all dynamic memory cells require a periodic refreshing of the stored data, so that unwanted modifications due to leakage are prevented before they occur. The use of a capacitor as the primary storage device generally enables the DRAM to be realized on a much smaller silicon area compared to the typical SRAM cell. Notice as the binary data is stored as charge in a capacitor, the DRAM cell must have access devices, or switches, which can be activated externally for "read" and "write" operations. But this requirement does not significantly affect the area advantage SRAM cell, since the cell access circuitry is usually very simple. Also, no static power is dissipated for storing charge on the capacitance. Consequently, dynamic RAM arrays can achieve higher integration densities than SRAM arrays.