Editing EPROM (section)

[[File:4Mbit EPROM Texas Instruments TMS27C040 (1).jpg|thumb|An EPROM: the [[Texas Instruments]] TMS27C040, a CMOS chip with 4 megabits of storage and 8-bit output (shown here in a 600-mil ceramic dual-in-line package). The TMS27C040 operates at 5 volts, but must be programmed at 13 volts.<ref>{{citation|title=TMS27C040 524,288 BY 8-BIT UV ERASABLE TMS27PC040 524,288 BY 8-BIT PROGRAMMABLE READ-ONLY MEMORY|author=Texas Instruments|date=1997}}</ref>]]
{{Confuse|EEPROM}}
{{Memory types}}
{{short description|Early type of solid state computer memory}}
An '''EPROM''' (rarely '''EROM'''), or '''erasable programmable read-only memory''', is a type of [[programmable read-only memory]] (PROM) [[integrated circuit|chip]] that retains its data when its power supply is switched off. Computer memory that can retrieve stored data after a power supply has been turned off and back on is called [[non-volatile]].  It is an array of [[floating-gate transistor]]s individually programmed by an electronic device that supplies higher voltages than those normally used in digital circuits.  Once programmed, an EPROM can be erased by exposing it to strong [[ultraviolet]] (UV) light source (such as from a [[mercury-vapor lamp]]). EPROMs are easily recognizable by the transparent [[fused quartz]] (or on later models' resin) window on the top of the package, through which the [[silicon]] chip is visible, and which permits exposure to ultraviolet light during erasing.<ref>{{Cite web|title=CPU History - EPROMs|url=http://www.cpushack.com/EPROM.html|access-date=2021-05-12|website=www.cpushack.com}}</ref>  It was invented by [[Dov Frohman]] in 1971.<ref name="computerhistory1971" />