Basic Electricity Explained (via YouTube)
This is a pretty cool basic video about how electricity works. Bonus points for the description of Ohm’s Law at the end (hint: it isn’t about math). (Source: http://www.youtube.com/)
Electrical
How to use a Multimeter (via YouTube)
This video is called “The Best Multimeter Tutorial (HD)” and I would have to say, it’s pretty damn good. If you work with electronics at all, and need to use a multimeter at some point, watch this video. Short and smart.
Ground Loops Demonstrated (via YouTube)
Even though this is demonstrated with a guitar amp, the principle still holds to other audio and electrical systems. Got a hum? Might be a ground loop. (Source: http://www.youtube.com/)