EPROM which is regarded as Erasable Programmable Read only Memory addresses the issue of ROM and PROM. EPROM erasing need some tools which emit some ultraviolet frequency which is configured with the EPROM programmer which offers voltage in specific levels in regards to the EPROM type used.
How EPROM Works
The cells on every intersection of the EPROM has two transistors which are separated using some thin oxide layer. The transistors are the control and floating gate which links only towards the row via the control gate. Provided the link is where it is, the value of the cell is one and changing it to zero needs some curious process which is Fowler-Nordheim tunneling. The tunneling is used in handling electronic placement on the floating gate. The electrical charge has a usual ten to thirteen volts range which is applied towards the floating gate. That charge is generated from bit line which drains in the ground through the floating gate.
The charge then leads to a floating-gate transistor which acts like the electron guns which are trapped and pushed through on the thin oxide layer another side that gives it negative charges. Such charged negative electrons may be barriers between the floating and control gate. If the gate has a greater flow than a charge of 50%, its value will be one. When the charge drops at the gate to below 50% threshold, then its value will change to zero. Every cell;l; is given the one value when every gate of EPROM is fully opened.
If you need an EPROM to be rewritten, you need to erase it where you need to supply strong energy level which can brake in negative electrons; hence it blocks a floating gate. In the EPROM, it will be accomplished using the UV light with 253.7 frequency since such frequency won’t penetrate most glasses or plastics because every EPROM has the quartz window on them. For the EPROM to work well, it needs to be close to one to two inches for the light source to be erased.
EPROM erases everything it needs to be removed then placed in the EPROM UV light eraser for some minutes. If you leave the EPROM for a longer time under the UV, it may be over-erased where floating EPROM gates may be charged until they won’t fully hold all electrons.