Broadly, there are two types of RAM. These are Static RAM and Dynamic RAM. Static RAM can hold information in their circuitry as long as there is power applied to it. The circuitry for static RAM comprises six CMOS transistors. This type of RAM does not need to be refreshed regularly, as it does not need extra power to prevent leakages.Dynamic RAM, on the other hand, comprises one capacitor and one transistor. Millions of these circuits are stored on a single chip to make up a DRAM. Since the circuitry of DRAM is comparatively small, the cost per unit of memory is lesser in DRAM.