A flash drive uses the concept of Electronically Erasable Programmable Read Only Memory (EEPROM). It has a printed circuit board with a grid of rows and columns. There are two transistors separated by a thin oxide layer, at each intersection of the grid. One of the transistors is called as 'floating gate' and the other is called 'control gate'. The process used to write/save/erase data from each block is called as tunneling.
In tunneling, a charge of 10 to 13 volts is sent to the electrons on the floating gate. The charged electrons are then given a negative charge by the oxide layer. These negatively charged electrons act like a barrier between the two gates. A call sensor then checks the charge flowing through the floating gate. If the charge of the flow is higher than one half of the original charge, then the value will be 1. If it is lesser than one half of the original charge, then the value will be 0. If the charge is less than one half of the original charge, that is the value is 0, we can change it to value 1 by the application of an electric field. In a flash drive, an in-circuit wiring is used to apply the electric field, either to the entire area or to predetermined blocks. This erases the targeted area, which can then be rewritten. This is the concept behind erasing/writing data on a flash drive. So, everytime you erase or write data, the electrons get charged and there is a change in their value from 0 to 1 or vice-versa. This was about what is flash drive and how does it work, let us now see some of the uses of flash drives.
