(WL), bit line (BL), and select lines (SL) without disturbing the other cells in the array. Characteristics NRAM has a density, at least in theory, similar to that of DRAM. DRAM includes capacitors, which are essentially two small metal plates with a thin insulator between them. NRAM has terminals and electrodes roughly the same size as the plates in a DRAM, the nanotubes between them being so much smaller they add nothing to the overall size. However it seems there is a minimum size at which a DRAM can be built, below which there is simply not enough charge being stored on the plates. NRAM appears to be limited only by lithography. This means that NRAM may be able to become much denser than DRAM, perhaps also less expensive. Unlike DRAM, NRAM does not require power to "refresh" it, and will retain its memory even after power is removed. Thus the power needed to write and retain the memory state of the device is much lower than DRAM, which has to build up charge on the cell plates. This means that NRAM might compete with DRAM in terms of cost, but also require less power, and as a result also be much faster because write performance is largely determined by the total charge needed. NRAM can theoretically reach performance similar to SRAM, which is faster than DRAM but much less dense, and thus much more expensive. Comparison with other non-volatile memory Compared with other non-volatile random-access memory (NVRAM) technologies, NRAM has several advantages. In flash memory, the common form of NVRAM, each cell resembles a MOSFET transistor with a control gate (CG) modulated by a floating gate (FG) interposed between the CG and the FG. The FG is surrounded by an insulating dielectric, typically an oxide. Since the FG is electrically isolated by the surrounding dielectric, any electrons placed on the FG will be trapped on the FG which screens the CG from the channel of the transistor and modifies the threshold voltage (VT) of the transistor. By writing and controlling the amount of charge placed on the FG, the FG controls the conduction state of the MOSFET flash device depending on the VT of the cell selected. The current flowing through the MOSFET channel is sensed to determine the state of the cell forming a binary code where a 1 state (current flow) when an appropriate CG voltage is