Differentiate between EPROM and EEPROM.

EPROM: The meaning of this term is Erasable PROM. This can be reprogrammed through first erasing the existing program. EPROM uses N-MOSFET array along with isolated gate structure.  The isolated transistor gate has no electrical link and it can store an electrical charge indefinitely. The data bits in EPROM memory array are represented through presence or absence of charge. Erasure is achieved with removing the gate charge. It can be UV EPROM or EEPROM.

The term UV EPROM implies Ultra Violet Erasable PROM. Erasure is achieved though using ultra violet light. The light passes throughout a window in the IC package to the chip where there are stored charges. Hence the stored contents are erased.

EEPROM: It means Electrically Erasable PROM. In EEPROM memory device, the erasure and programming is done through electrical pulses.