Wednesday, 17 August 2016

electric circuits - Internal resistor in a diode


When we talk about the resistance of a diode (of the P and N region), is this resistance like the one inside an Electro-Motive Force or it acts like a normal resistor (external electric field exist)?


I was reading a book called Fundamentals of Microelectronics by Behzad Razavi and in its introduction of semiconductor, P and N Semiconductors acts like a normal resistor (External electric field is applied to make a drift current inside it)(See pics) but when studying about the diode, it mentions that a drift current is present in the diode because of the electric field of depletion region.drift current in a semiconductor


And Talking about a diode, if the P and N region acts like a resistor, so when there is a positive EMF applied to a diode, external electric field appears in the P and N region like a resistor and then P and N region has a drift current but also there is a diffusion current due to difference of concentration of holes and electrons, so is this external electric field acting on the diffusion current in the P and N region?



All in all, Im confused about this resistance, can somebody explain it to me.




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