capacitor (PHYSICS)

https://learn.sparkfun.com/tutorials/capacitors --definition

https://en.wikipedia.org/wiki/Types_of_capacitor --types

http://www.audiomasterclass.com/auralize/the-principle-of-operation-of-a-capacitor-condenser-microphone --operation

http://www.learningaboutelectronics.com/Articles/Capacitor-characterisitics-and-specifications.php --specifications

http://www.rfcafe.com/references/electrical/capacitance.htm --capacity

https://en.wikipedia.org/wiki/Applications_of_capacitors --connection and equipment

http://www.aerovox.com/IndustrialProductsGroup/IndustrialApplications.aspx --use in industry