Static RAM: No refreshing, 6 to 8 MOS transistors are 
required to form one memory cell, Information stored as 
voltage level in a flip flop. 
Dynamic RAM: Refreshed periodically, 3 to 4 transistors are 
required to form one memory cell, Information is stored as 
a charge in the gate to substrate capacitance.

Dynamic RAM:-Dram stores the data in the form of charge 
into capacitor.for storing another charge capacitor require 
to refresh the data which it holds.This refresh operation 
is where dynamic RAM gets its name. 

Static RAM:-is a type of semiconductor memory where the 
word static indicates that, unlike dynamic RAM (DRAM), it 
does not need to be periodically refreshed, as SRAM uses 
bistable latching circuitry to store each bit.

•	Static ram is more reliable and expensive than DRAM

•	A static memory cell takes a lot more space on a 
chip than a dynamic memory cell.
•	Static RAM is used to create the CPU's speed-
sensitive cache, while dynamic RAM forms the larger system 
RAM space.