Comments by "Liam" (@1495978707) on "This is How Diodes Work" video.

  1. 3:50 Something that you should’ve pointed out is that the P and N doped pieces are still charge neutral, only the depletion region has net charges because of diffusion. That is, when concentration of something isn’t uniform, it tries to spread out 4:35 This is backwards, when reverse bias is applied, the depletion region shrinks to nothing. Then you’re trying to pull electrons from the p type and holes from the n type, which is very difficult to do. With forward bias, some of the electrons in the p side of the depletion region get replaced by holes and vice versa on the other side, and then the depletion region tries to keep equilibrium by diffusion. The reason that this requires some voltage to start is to cancel out the field set up in the depletion region.
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