EPROM silicon chip Coloured Scanning Electron Micrograph SEM of the etched surface of part of an EPROM silicon chip Here narrow tracks form part of the chips circuitry at left are rows of memory cells This is an integrated circuit The chip is of the EPROM type Electrically Programmable ReadOnly Memory EPROM chips are programmed by applying a voltage across selected connecting pins The memory cells can be switched electrically so that the chip stores the information programmed into it By shining ultra violet light on the chip the programming is erased and it can then be reprogrammed Magnification x at xcm size