Diodes - PN Junctions
Channel: ElectronX Lab
Date: 2012-01-03

Audio is not good in this video. Try this one instead: 

https://youtu.be/KDAnGZf25VE

A description of PN junctions, unbiased, reverse biased and forward biased.

I used the builtin laptop microphone, so the audio is not all that great.  I thought the external one was automatically selected, but I forgot to double check.